Submission

def strategy(opponent_source: str) -> str:

    # a very simple strategy - defect if we have the slightest suspicion that the opponent will defect, cooperate otherwise

    return 'defect' if 'defect' in opponent_source else 'cooperate'

​

​

# you can remove this driver code as long as you make sure that you read the opponent's code from stdin, and write your decision to stdout

def driver():

    import sys

    opponent_source = ''.join(l for l in sys.stdin)

    print(strategy(opponent_source))

​

​

driver()