#!/usr/bin/python3

class Computer:

    def __init__(self, instructions=[], break_on_exec=0):
        self.__acc__=0
        self.__pos__=0
        self.__instructions__=instructions
        self.__executed_count__={}
        self.__keep_running__=True
        self.__break_on_exec_number__=break_on_exec
        self.__exited_on_break__=False

    def set_instructions(self, instructions):
        self.__instructions__=instructions

    def run(self):
        while self.keep_running():
            self.run_command()
        # when we're done, return the accumulator
        return self.__acc__

    def keep_running(self):
        if self.__pos__ >= len(self.__instructions__):
            self.__keep_running__=False
        return self.__keep_running__

    def exited_on_break(self):
        return self.__exited_on_break__

    def run_command(self):
        if self.__pos__ in self.__executed_count__:
            self.__executed_count__[self.__pos__]+=1
        else:
            self.__executed_count__[self.__pos__]=1

        if self.__break_on_exec_number__ > 0 and self.__executed_count__[self.__pos__] >= self.__break_on_exec_number__:
            self.__keep_running__=False
            self.__exited_on_break__=True
            return
        else:
            (instruction,param) = self.__instructions__[self.__pos__]
            if instruction == "nop":
                # do nothing, except increment the program counter
                self.__pos__+=1
            elif instruction == "acc":
                val=int(param)
                self.__acc__+=val
                self.__pos__+=1
            elif instruction == "jmp":
                val=int(param)
                self.__pos__+=val
            else:
                raise Exception("WTAF - that's not a real instruction!")
        return

def main():
    instructions = [line.rstrip().split(" ") for line in open("input.txt", "r")]
    comp = Computer(instructions, break_on_exec=2)

    print("Acc was {} when computer finished.".format(comp.run()))

if __name__ == "__main__":
    main()