You are given a code:

def main_solution(x):
    return (func_4('hcfub') + ('pap' + 'pex'))

Can you predict the output of `main_solution("fwnfynlz")` 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": "fwnfynlz"}, "ref_output": "hcfubpappex", "ref_code": "def main_solution(x):\n    return (func_4('hcfub') + ('pap' + 'pex'))", "funcname": "main_solution"}
rule