Task: Question Answering
Input (English): Passage: The film shows a scene of a girl being kidnapped from a charity plane by Vietnamese rebels (a U.N. supplies [as in food and medicine] plane) in Vietnam.  Then we are taken to the United States to a detention center in Los Angeles where the warden of the center and 6 of the toughest prisoners are hired to rescue the girl, whose name is Gabrielle Presscott, daughter of Jameson Prescott, CEO and billionaire.  Warden Toliver and prisoners (by last name only, their first names are never revealed) Butts and Monster (black youths), Lopez and Vasquez (Latino youths, with Vasquez being a girl), and Brophy and Lamb (white youths). The group travels to Vietnam with three days to rescue Gabrielle, spending one day to train and the rest of the days to find her.
After winning a battle the group spends the night at a village brothel and has a small celebration, with Brophy sneaking away into the night.  The group awakens to find the rebels with Brophy as a hostage and asking the villagers to hand over the rest of the Americans.  The group decides to attempt a rescue for Brophy and are successful, however, Lopez and Monster are both killed during the fight. The group runs away into the jungle and is tiredly marching along when Lamb steps on a landmine.  While Toliver is trying to disarm the mine, some rebels are slowly getting nearer and nearer to the group.  Brophy once again sneaks away but sacrifices himself, bringing another death to the group.  Toliver and his men finally arrive at the rebel base camp, with Toliver combing the camp for Gabrielle.  After he finds her he returns to the others and hands each of them a set of explosives to be detonated by a timer. 
Question: What are the names of the characters who rescue the character who eventually sacrifices himself for the group?
Output (English): Butts.