Given the task definition and input, reply with output. In this task, you will use your knowledge about language (and common sense) to determine what element the marked number refers to. The numbers are marked with two underlines around them, like: _ number _. Your answer should be chosen from the given text, and should not contain other words.

Lisa: He treats everyone like shit . He 's always mean . He 's always cruel . He beats you up .
Lisa: He 's even too weird for Ali and she 's into everything ! He 's the source of everybody 's troubles , Marty . And even still , he 's going to finish high school and go to college and probably get rich .
Marty: Yeah , and I 'm going to be delivering pizzas to him in Weston . How would we get a gun ?
Lisa: My ma has _ one _ .
Marty: Shit ! That motherfucker ! He 's fucking dissed me ... he 's fucking treated me like shit my whole goddamn life !
Lisa: Let 's kill him .
Marty: No
Marty: shit .
gun