MASH

The plot is told as a series of (presumably chronological) vignettes surrounding the life of the namesake Mobile Army Surgical Hospital where it is set. While the episodic film lacks the cohesion of an overarching singular plot with a traditional narrative structure, the vignettes do present a clear means for the film to explore the themes of military life.
Set in 1951 in South Korea, the 4077th Mobile Army Surgical Hospital is assigned two replacements: Captains "Hawkeye" Pierce and "Duke" Forrest, who arrive in a stolen Jeep. They are insubordinate, womanizing, mischievous rule-breakers, but they soon prove to be excellent combat surgeons. As the film progresses, further scenes introduce additional characters. Some characters are already at the camp when Hawkeye and Duke arrive, such as the bumbling commander Henry Blake, his hyper-competent chief clerk Radar O'Reilly, the morose dentist Walter "Painless" Waldowski, the incompetent and pompous surgeon Frank Burns, and the contemplative Chaplain Father Mulcahy. Other characters arrive after Hawkeye and Duke, and become integrated into camp life, such as surgeon Trapper John and Nurse Margaret Houlihan. After the characters are introduced, which forms the opening act, further comedic episodes explore the evolving relationships between the characters.
The main characters in the camp divide into two factions; Hawkeye, Duke, and Trapper John form one faction; all three were drafted into the army and are not as dedicated to the mission or lifestyle of the military. They are prone to pranks and heavy drinking. The other faction forms around the romantic relationship between Majors Houlihan and Burns, who are both career military personnel. The two factions battle back and forth in a series of pranks and reprisals (one involving exposing a naked Houlihan to the camp when the walls of the shower tent are collapsed, another embarrassing the couple by exposing their heretofore secret romance) until Burns is goaded into punching Hawkeye and removed from the unit for psychiatric evaluation. The removal of Burns changes the camp social dynamic and marks the transition to the third act.
Trapper and Hawkeye are removed to Japan to operate on a congressman's son. When they later perform an unauthorized operation on a local infant, they face discipline by the hospital commander for misusing army resources until they drug him and stage pictures with a prostitute, saving themselves through blackmail. Upon returning to Korea, General Hammond and Colonel Blake organize a "friendly" football game, with some money thrown into a pot to make bets ($5,000 or $6,000). Hawkeye and Blake arrange for a plan in order to assure victory. First, they get Henry to apply for a specific neurosurgeon: Dr. Oliver Harmon Jones, a former professional football player for the San Francisco 49ers. Then, they bet half their money up front and keep the ringer (Jones) out of the first half of the game. During the game, Houlihan uncharacteristically participates as a cheerleader in an effort to fit in. Once the other team racks up some easy points and becomes confident enough to offer good odds to bet the rest of the money, the 4077th brings in Jones for the second half. The 325th has its own ringers, however, and the 4077th fights back with illegal injuries and by drugging the 325th's running back. The game comes down to the last play, in which the quarterback (Trapper) returns the ball to the center, SSgt. Vollmer, who hides the ball under his jersey and runs into the end zone for the winning touchdown.
Not long after the football game, Hawkeye and Duke get their discharge orders and begin their journey homeâin the same stolen Jeep in which they arrived.

Question: Who participates as a cheerleader?
Answer: Houlihan