You are given a code:

def main_solution(x):
    return ('soo' + 'fgokes')

Can you predict the output of `main_solution("cfosttkbfg")` without writing any code? Please reason and put your final answer in the following json format: {"output": <your output>}, where <your output> should be the final string.
user
{"ref_input": {"x": "cfosttkbfg"}, "ref_output": "soofgokes", "ref_code": "def main_solution(x):\n    return ('soo' + 'fgokes')", "funcname": "main_solution"}
rule