2024 Major League Soccer season

Major League Soccer
Season2024
Dates
  • February 21 – October 19
    (regular season)
  • October – December 7
    (playoffs)
Matches played238
Goals scored698 (2.93 per match)
Top goalscorerCristian Arango
(16 goals)
Biggest home winMiami 5–0 Orlando
(March 2)
LAFC 5–0 Nashville
(March 23)
Seattle 5–0 Montréal
(April 6)
Biggest away winChicago 0–4 Salt Lake
(April 20)
Highest scoring8 goals:
Miami 6–2 RBNY
(May 4)
Salt Lake 5–3 Colorado
(May 18)
Longest winning run7 matches:
Cincinnati
(April 20 – May 25)
Longest unbeaten run13 matches:
Salt Lake
(March 23 – present)
Longest winless run10 matches:
Kansas City
(April 7 – June 1)
Longest losing run7 matches:
Kansas City
(April 27 – June 1)
Highest attendance72,610
SKC 2-3 MIA (April 13)[1]
Lowest attendance16,223
COL 1–1 NSH (March 2)
Average attendance25,805
2023
2025
All statistics correct as of March 9, 2024.

The 2024 Major League Soccer season is the ongoing 29th season of Major League Soccer (MLS), the top professional soccer league in the United States and Canada, and the 46th season overall of a national first-division league in the United States.

The league's 29 teams are divided into the Eastern and Western conferences. This is the first season since the 2016 season to have no new expansion teams joining MLS; San Diego FC is scheduled to join the league in 2025.[2] FC Cincinnati are the reigning Supporters' Shield holders; the Columbus Crew are the reigning MLS Cup champions.[3]

Pre-season matches ran from January 19 through February 17.[4] The regular season began on February 21 and is scheduled to end on October 19, with a pause from mid-July to mid-August for the 2024 Leagues Cup, which comprises all MLS and Liga MX teams. The 2024 MLS Cup Playoffs are scheduled to begin in October and conclude with MLS Cup 2024 on December 7.[5] MLS will only send 8 senior squads to the 2024 U.S. Open Cup as part of a compromise with the USSF that allows most teams to be represented by MLS Next Pro teams.[6]

This is the second season that Apple and MLS will be part of a ten-year partnership for the broadcast and streaming rights to all MLS and Leagues Cup games, as well as select MLS Next and MLS Next Pro games, on the MLS Season Pass service within the Apple TV app.[7]

Teams[edit]

Stadiums and locations[edit]

Team Stadium Capacity
Atlanta United FC Mercedes-Benz Stadium[A] 42,500
Austin FC Q2 Stadium 20,738
Charlotte FC Bank of America Stadium[A] 38,000[8]
Chicago Fire FC Soldier Field[A] 24,955
FC Cincinnati TQL Stadium 26,000
Colorado Rapids Dick's Sporting Goods Park 18,061
Columbus Crew Lower.com Field 20,011
FC Dallas Toyota Stadium 20,500
D.C. United Audi Field 20,000
Houston Dynamo FC Shell Energy Stadium 22,039
LA Galaxy Dignity Health Sports Park 27,000
Los Angeles FC BMO Stadium 22,000
Minnesota United FC Allianz Field 19,400
Inter Miami CF Chase Stadium[B] 21,550
CF Montréal Saputo Stadium 19,619
Nashville SC Geodis Park 30,000
New England Revolution Gillette Stadium[A] 20,000
New York City FC Yankee Stadium[A]
Citi Field[A]
28,743
41,992
New York Red Bulls Red Bull Arena 25,000
Orlando City SC Inter&Co Stadium 25,500
Philadelphia Union Subaru Park 18,500
Portland Timbers Providence Park 25,218
Real Salt Lake America First Field 20,213
San Jose Earthquakes PayPal Park 18,000
Seattle Sounders FC Lumen Field[A] 37,722
Sporting Kansas City Children's Mercy Park 18,467
St. Louis City SC CityPark 22,500
Toronto FC BMO Field 28,351
Vancouver Whitecaps FC BC Place[A] 22,120
  1. ^
    Non-soccer specific stadium and artificially reduced capacity. Capacity may be increased to full capacity if demand requires.
  2. ^
    Temporary stadium.

Personnel and sponsorships[edit]

Note: All teams use Adidas as universal kit manufacturer. As part of Apple's broadcast contract, all MLS kits will include Apple TV+ as a sleeve sponsor.[9]

Team Head coach Captain Shirt sponsor Sleeve sponsor
Atlanta United FC United States Rob Valentino (interim) United States Brad Guzan American Family Insurance Piedmont Hospital
Austin FC United States Josh Wolff Argentina Sebastián Driussi Yeti Netspend
Charlotte FC England Dean Smith England Ashley Westwood Ally Centene
Chicago Fire FC United States Frank Klopas Switzerland Xherdan Shaqiri Carvana[10] Magellan
FC Cincinnati United States Pat Noonan Argentina Luciano Acosta Mercy Health Kroger
Colorado Rapids United States Chris Armas United States Keegan Rosenberry UCHealth
Columbus Crew France Wilfried Nancy United States Darlington Nagbe Nationwide Tipico
FC Dallas France Peter Luccin (interim) United States Paul Arriola Children's Health (home)
UT Southwestern (away)
D.C. United United States Troy Lesesne United States Steve Birnbaum Guidehouse The Fruitist
Houston Dynamo FC United States Ben Olsen Mexico Héctor Herrera MD Anderson
Inter Miami CF Argentina Gerardo Martino Argentina Lionel Messi Royal Caribbean Fracht Group
LA Galaxy United States Greg Vanney Japan Maya Yoshida Herbalife
Los Angeles FC United States Steve Cherundolo Spain Ilie Sánchez BMO Bank Ford
Minnesota United FC Wales Eric Ramsay United States Wil Trapp Target Allianz
CF Montréal France Laurent Courtois Canada Samuel Piette Bank of Montreal Telus
Nashville SC Canada Rumba Munthali (interim) United States Walker Zimmerman Renasant Bank Hyundai
New England Revolution United States Caleb Porter Spain Carles Gil UnitedHealth Santander
New York City FC England Nick Cushing Brazil Thiago Martins Etihad Airways Capital Rx
New York Red Bulls Germany Sandro Schwarz Sweden Emil Forsberg Red Bull OANDA
Orlando City SC Colombia Óscar Pareja Sweden Robin Jansson Orlando Health Exploria
Philadelphia Union United States Jim Curtin United States Alejandro Bedoya Bimbo Bakeries USA Independence Blue Cross
Portland Timbers England Phil Neville Colombia Diego Chará DaBella (1 game)[11]
Tillamook (rest of season)[12]
TikTok
Real Salt Lake United States Pablo Mastroeni Colombia Cristian Arango Select Health Intermountain Health
San Jose Earthquakes United States Luchi Gonzalez United States Jackson Yueill Intermedia PayPal
Seattle Sounders FC United States Brian Schmetzer Switzerland Stefan Frei Providence Emerald Queen Casino
Sporting Kansas City United States Peter Vermes Scotland Johnny Russell Compass Minerals
St. Louis City SC South Africa Bradley Carnell Switzerland Roman Bürki Purina BJC HealthCare
Toronto FC England John Herdman Canada Jonathan Osorio Bank of Montreal GE Appliances
Vancouver Whitecaps FC Italy Vanni Sartini Scotland Ryan Gauld Telus

Coaching changes[edit]

Team Outgoing coach Manner of departure Date of vacancy Position in table Incoming coach Date of appointment
Portland Timbers United States Miles Joseph (interim) End of interim period November 6, 2023 Pre-season England Phil Neville November 6, 2023[13]
Charlotte FC Italy Christian Lattanzio Mutual consent November 8, 2023[14] England Dean Smith December 12, 2023[15]
CF Montréal Argentina Hernán Losada November 9, 2023[16] France Laurent Courtois January 8, 2024[17]
New York Red Bulls United States Troy Lesesne End of contract November 14, 2023[18] Germany Sandro Schwarz December 14, 2023[19]
Colorado Rapids Scotland Chris Little (interim) End of interim period November 17, 2023 United States Chris Armas November 17, 2023[20]
Chicago Fire FC United States Frank Klopas (interim) December 5, 2023 United States Frank Klopas December 5, 2023[21]
Minnesota United FC England Sean McAuley (interim) January 5, 2024 New Zealand Cameron Knowles (interim) January 5, 2024[22]
D.C. United France Frédéric Brillant (interim) January 10, 2024 United States Troy Lesesne January 10, 2024[23]
New England Revolution United States Clint Peay (interim) December 19, 2023 United States Caleb Porter December 19, 2023[24]
Minnesota United FC New Zealand Cameron Knowles (interim) March 13, 2024 2nd in West, 3rd Overall Wales Eric Ramsay March 13, 2024[25]
Nashville SC England Gary Smith Mutual consent May 16, 2024 10th in East, 19th Overall Canada Rumba Munthali (interim) May 16, 2024[26]
Atlanta United FC Mexico Gonzalo Pineda Fired June 3, 2024 13th in East, 24th Overall United States Rob Valentino (interim) June 3, 2024[27]
FC Dallas Spain Nico Estévez June 9, 2024 13th in West, 27th Overall France Peter Luccin (interim) June 9, 2024[28]

Regular season[edit]

Format[edit]

The regular season consists of 34 matches for each team, split evenly between home and away games. The opening match was played on February 21, the earliest in league history; the regular season will end with Decision Day on October 19, which will comprise simultaneous intra-conference matches. Matches will be paused from July 26 to August 25 for the 2024 Leagues Cup, a knockout tournament that includes teams from MLS and Liga MX. The league will not pause matches for the 2024 Copa América, which will be played in the United States from June to July. Most regular season matches will be played on Saturdays and Wednesdays at 7:30 p.m. local time.[29][30]

The 29 teams are divided into two conferences: the Eastern and Western. The 15 teams in the East will play a round-robin format with intra-conference teams and six matches against six opponents from the West. The 14 teams in the West will play a round-robin with intra-conference teams, an additional one or two intra-conference matches, and six to seven matches against opponents from the East.[29][31] The top nine teams in each conference will advance to the 2024 MLS Cup Playoffs, which begin with a wild card round for the eighth and ninth placed teams and is followed by a best-of-three series that was introduced in 2023. The remaining matches are single-elimination and culminate with the MLS Cup final on December 7.[30][32]

Several new rules were scheduled to be introduced for the 2024 season following trials in MLS Next Pro, including in-stadium announcements of video assistant referee decisions, a time limit for substitutions, and mandatory off-field checks for injured players.[33] These initiatives were postponed by MLS due to an ongoing labor dispute with the Professional Soccer Referees Association, who organized a lockout of their referees.[34][35] Replacement referees from outside the union, including former officials and those from lower level leagues other than USL, were called in to officiate MLS matches.[36][37] The referees' union and MLS reached an agreement in time for the regular referees to return to the field for Matchday 7, on March 30.[38]

The 2024 MLS All-Star Game will be played between the MLS All-Stars and the Liga MX All-Stars on July 24.[39]

Conference standings[edit]

MLS Eastern Conference table (2024)
Pos Team Pld W L T GF GA GD Pts Qualification
1 Inter Miami CF 18 10 3 5 42 27 +15 35 Qualification for Round One and the CONCACAF Champions Cup Round One
2 FC Cincinnati 16 10 3 3 23 16 +7 33 Qualification for Round One
3 New York City FC 16 9 5 2 24 17 +7 29
4 New York Red Bulls 17 8 4 5 29 23 +6 29
5 Charlotte FC 17 7 6 4 18 18 0 25
6 Toronto FC 17 7 7 3 26 26 0 24
7 Columbus Crew 14 6 2 6 21 13 +8 24
8 Philadelphia Union 16 4 4 8 27 23 +4 20 Qualification for the Wild card round
9 Nashville SC 16 4 5 7 20 22 −2 19
10 D.C. United 17 4 6 7 25 31 −6 19
11 Orlando City SC 16 4 7 5 16 24 −8 17
12 CF Montréal 16 4 7 5 23 35 −12 17
13 Atlanta United FC 16 4 8 4 22 21 +1 16
14 Chicago Fire FC 17 3 8 6 17 29 −12 15
15 New England Revolution 15 4 10 1 12 27 −15 13
Updated to match(es) played on June 8, 2024. Source: MLS
Rules for classification: 1) points; 2) total wins; 3) total goal differential; 4) total goals scored; 5) fewer disciplinary points; 6) away goal differential; 7) away goals scored; 8) home goals differential; 9) home goals scored; 10) coin toss (2 clubs tied) or drawing of lots (≥3 clubs tied)
MLS Western Conference table (2024)
Pos Team Pld W L T GF GA GD Pts Qualification
1 Real Salt Lake 17 9 2 6 36 19 +17 33 Qualification for Round One and the CONCACAF Champions Cup Round One
2 Los Angeles FC 16 9 4 3 28 19 +9 30 Qualification for Round One
3 Minnesota United FC 16 8 3 5 28 21 +7 29
4 LA Galaxy 17 7 3 7 31 25 +6 28
5 Vancouver Whitecaps FC 16 7 5 4 24 19 +5 25
6 Austin FC 17 6 6 5 21 25 −4 23
7 Houston Dynamo FC 16 6 6 4 18 18 0 22
8 Colorado Rapids 17 6 7 4 29 31 −2 22 Qualification for the Wild card round
9 Portland Timbers 18 5 7 6 32 32 0 21
10 Seattle Sounders FC 17 4 7 6 20 21 −1 18
11 St. Louis City SC 16 3 4 9 23 25 −2 18
12 Sporting Kansas City 17 3 9 5 26 32 −6 14
13 FC Dallas 16 3 8 5 18 25 −7 14
14 San Jose Earthquakes 16 3 11 2 24 39 −15 11
Updated to match(es) played on June 8, 2024. Source: MLS
Rules for classification: 1) points; 2) total wins; 3) total goal differential; 4) total goals scored; 5) fewer disciplinary points; 6) away goal differential; 7) away goals scored; 8) home goals differential; 9) home goals scored; 10) coin toss (2 clubs tied) or drawing of lots (≥3 clubs tied)

Overall table[edit]

The leading team in this table will win the Supporters' Shield.

Overall MLS standings table
Pos Team Pld W L T GF GA GD Pts Qualification
1 Inter Miami CF 18 10 3 5 42 27 +15 35 Qualification for the CONCACAF Champions Cup Round One[a]
2 FC Cincinnati 16 10 3 3 23 16 +7 33 Qualification for the CONCACAF Champions Cup Round One[b]
3 Real Salt Lake 17 9 2 6 36 19 +17 33 Qualification for the CONCACAF Champions Cup Round One[c]
4 Los Angeles FC 16 9 4 3 28 19 +9 30 Qualification for the CONCACAF Champions Cup Round One[d]
5 New York City FC 16 9 5 2 24 17 +7 29 Qualification for the U.S. Open Cup Round of 32[e]
6 Minnesota United FC 16 8 3 5 28 21 +7 29
7 New York Red Bulls 17 8 4 5 29 23 +6 29
8 LA Galaxy 17 7 3 7 31 25 +6 28
9 Vancouver Whitecaps FC 16 7 5 4 24 19 +5 25
10 Charlotte FC 17 7 6 4 18 18 0 25 Qualification for the U.S. Open Cup Round of 32[e]
11 Toronto FC 17 7 7 3 26 26 0 24
12 Columbus Crew 14 6 2 6 21 13 +8 24 Qualification for the U.S. Open Cup Round of 32[e]
13 Austin FC 17 6 6 5 21 25 −4 23
14 Houston Dynamo FC 16 6 6 4 18 18 0 22
15 Colorado Rapids 17 6 7 4 29 31 −2 22
16 Portland Timbers 18 5 7 6 32 32 0 21
17 Philadelphia Union 16 4 4 8 27 23 +4 20
18 Nashville SC 16 4 5 7 20 22 −2 19
19 D.C. United 17 4 6 7 25 31 −6 19
20 Seattle Sounders FC 17 4 7 6 20 21 −1 18
21 St. Louis City SC 16 3 4 9 23 25 −2 18
22 Orlando City SC 16 4 7 5 16 24 −8 17
23 CF Montréal 16 4 7 5 23 35 −12 17
24 Atlanta United FC 16 4 8 4 22 21 +1 16
25 Chicago Fire FC 17 3 8 6 17 29 −12 15
26 Sporting Kansas City 17 3 9 5 26 32 −6 14
27 FC Dallas 16 3 8 5 18 25 −7 14
28 New England Revolution 15 4 10 1 12 27 −15 13
29 San Jose Earthquakes 16 3 11 2 24 39 −15 11
Updated to match(es) played on June 8, 2024. Source: MLS
Rules for classification: 1) points; 2) total wins; 3) total goal differential; 4) total goals scored; 5) fewer disciplinary points; 6) away goal differential; 7) away goals scored; 8) home goals differential; 9) home goals scored; 10) coin toss (2 clubs tied) or drawing of lots (≥3 clubs tied)
Notes:
  1. ^ As 2024 MLS Supporters' Shield champions
  2. ^ As highest-ranked club in 2024 MLS Supporters' Shield not already qualified
  3. ^ As 2024 Western Conference regular season champions
  4. ^ As second highest-ranked club in 2024 MLS Supporters' Shield not already qualified
  5. ^ a b c As one of the top seven US teams in the overall table to not qualify for the 2025 CONCACAF Champions Cup

MLS All-Star Game[edit]

MLS All-Stars United States CanadavMexico Liga MX All-Stars

2025 FIFA Club World Cup[edit]

The United States will be the host country for the 2025 FIFA Club World Cup. MLS clubs can qualify as a host nation club; however, the criteria for selection has not been announced. MLS clubs have also been able to qualify through the 2021–2024 editions of the CONCACAF Champions Cup/CONCACAF Champions League.

Seattle Sounders FC have qualified as the 2022 CONCACAF Champions League winners.[40]

Attendance[edit]

Average home attendances[edit]

As of 8 May 2024
Rank Team GP Cumulative High Low Mean
1 Atlanta United FC 9 428,743 67,727 42,525 47,638
2 Charlotte FC 9 306,018 62,291 27,021 34,002
3 Seattle Sounders FC 7 211,114 31,102 29,244 30,159
4 New England Revolution 8 237,787 65,612 14,557 29,723
5 Vancouver Whitecaps FC 8 232,678 51,035 22,178 29,085
6 Nashville SC 10 283,656 30,109 26,842 28,366
7 Toronto FC 8 207,987 28,261 24,108 25,998
8 FC Cincinnati 8 201,953 25,513 24,282 25,244
9 Sporting Kansas City 9 219,719 72,610 17,046 24,413
10 LA Galaxy 7 167,319 27,642 19,505 23,903
11 Orlando City SC 8 181,797 25,046 20,985 22,725
12 St. Louis City SC 9 202,038 22,500 22,423 22,449
13 Los Angeles FC 9 199,108 22,321 22,010 22,123
14 Portland Timbers 8 176,316 25,218 19,113 22,040
15 New York City FC 9 197,205 30,731 18,623 21,912
16 Inter Miami CF 10 212,442 21,550 20,793 21,244
17 Austin FC 9 186,642 20,738 20,738 20,738
18 Columbus Crew 7 144,228 20,927 20,314 20,604
19 Real Salt Lake 8 140,338 21,078 19,357 20,048
20 New York Red Bulls 7 79,529 25,219 17,501 19,882
21 CF Montréal 6 117,714 19,619 19,619 19,619
22 Minnesota United FC 9 175,197 19,906 18,652 19,466
23 San Jose Earthquakes 7 136,076 43,774 13,744 19,439
24 FC Dallas 7 133,645 19,096 19,069 19,092
25 Philadelphia Union 8 150,474 19,048 18,525 18,809
26 D.C. United 9 166,770 19,365 17,237 18,530
27 Chicago Fire FC 10 183,906 26,592 11,372 18,391
28 Houston Dynamo FC 8 144,196 22,039 15,237 18,025
29 Colorado Rapids 7 94,481 16,223 7,492 13,497
Total 238 5,519,076 72,610 7,492 23,189

Highest attendances[edit]

Regular season

Rank Home team Score Away team Attendance Date Matchday Stadium Ref.
1 Sporting Kansas City 2–3 Inter Miami CF 72,610 April 13, 2024 9 Arrowhead Stadium [1]
2 Atlanta United FC 4–1 New England Revolution 67,727 March 9, 2024 4 Mercedes-Benz Stadium [41]
3 New England Revolution 1–4 Inter Miami CF 65,612 April 27, 2024 11 Gillette Stadium [42]
4 Charlotte FC 1–0 New York City FC 62,291 February 24, 2024 2 Bank of America Stadium [43]
5 Atlanta United FC 2–3 Charlotte FC 61,209 June 2, 2024 18 Mercedes-Benz Stadium [44]
6 Vancouver Whitecaps FC 1–2 Inter Miami CF 51,035 May 25, 2024 16 BC Place [45]
7 San Jose Earthquakes 3–1 Los Angeles FC 43,774 May 4, 2024 12 Levi's Stadium [46]
8 Atlanta United FC 1–2 Minnesota United FC 43,338 May 4, 2024 12 Mercedes-Benz Stadium [47]
9 Atlanta United FC 0–1 Los Angeles FC 43,128 May 25, 2024 16 Mercedes-Benz Stadium [48]
10 Atlanta United FC 2–3 D.C. United 42,822 May 11, 2024 13 Mercedes-Benz Stadium [49]

Player statistics[edit]

As of 8 June 2024

Source:[50]

Goals[edit]

Rank Player Club Goals[51]
1 Colombia Cristian Arango Real Salt Lake 16
2 Belgium Christian Benteke D.C. United 13
3 Argentina Lionel Messi Inter Miami CF 12
Uruguay Luis Suárez
5 Gabon Denis Bouanga Los Angeles FC 10
Hungary Dániel Gazdag Philadelphia Union
7 Serbia Dejan Joveljić LA Galaxy 9
Scotland Lewis Morgan New York Red Bulls
Brazil Rafael Navarro Colorado Rapids
10 Colombia Andrés Gómez Real Salt Lake 8
Chile Felipe Mora Portland Timbers

Hat-tricks[edit]

Player For Against Score Date
Belgium Christian Benteke D.C. United New England Revolution 3–1 (H) February 24, 2024
Greece Giorgos Giakoumakis Atlanta United FC New England Revolution 4–1 (H) March 9, 2024
Scotland Lewis Morgan New York Red Bulls Inter Miami CF 4–0 (H) March 23, 2024
Colombia Cristian Arango Real Salt Lake St. Louis City SC 3–1 (H) March 30, 2024
Uruguay Luis Suárez Inter Miami CF New York Red Bulls 6–2 (H) May 4, 2024
England Sam Surridge Nashville SC CF Montréal 4–1 (H)
Belgium Christian Benteke D.C. United Atlanta United FC 2–3 (A) May 11, 2024
Italy Federico Bernardeschi Toronto FC CF Montréal 5–1 (H) May 18, 2024
Costa Rica Alonso Martínez New York City FC San Jose Earthquakes 5–1 (H) May 31, 2024
Colombia Cristian Arango Real Salt Lake Austin FC 5–1 (H) June 1, 2024
Notes

(H) – Home team
(A) – Away team

Assists[edit]

Rank Player Club Assists[52]
1 Argentina Lionel Messi Inter Miami CF 13
2 Argentina Luciano Acosta FC Cincinnati 10
Finland Robin Lod Minnesota United FC
4 Colombia Cristian Arango Real Salt Lake 9
Argentina Cristian Espinoza San Jose Earthquakes
6 Brazil Evander Portland Timbers 8
Spain Riqui Puig LA Galaxy
United States Jared Stroud D.C. United
9 Poland Mateusz Klich 7
United States Diego Luna Real Salt Lake
Honduras Joseph Rosales Minnesota United FC
Belgium Dante Vanzeir New York Red Bulls

Clean sheets[edit]

Rank Player Club Clean
sheets[53]
1 Croatia Kristijan Kahlina Charlotte FC 7
France Hugo Lloris Los Angeles FC
3 Switzerland Roman Bürki St. Louis City SC 5
United States Roman Celentano FC Cincinnati
United States Brad Stuver Austin FC
6 United States Drake Callender Inter Miami CF 4
United States Sean Johnson Toronto FC
United States Patrick Schulte Columbus Crew
Japan Yohei Takaoka Vancouver Whitecaps FC
United States Joe Willis Nashville SC

Awards[edit]

Team/Player of the Matchday[edit]

  • Bold denotes the Player of the Matchday.

Goal of the Matchday[edit]

Player of the Month[edit]

Month Player Club Stats Ref.
February/March Uruguay Luis Suárez Inter Miami CF 7 matches played, 5 goals, 3 assists [106]
April Argentina Lionel Messi Inter Miami CF 4 matches played, 6 goals, 4 assists [107]
May Argentina Luciano Acosta FC Cincinnati 6 matches played, 3 goals, 5 assists [108]

See also[edit]

References[edit]

  1. ^ a b