You are given a code:

def main_solution(x):
    return (func_15('mmm') + func_20('pwxup', 'icfenw'))

Can you predict the output of `main_solution("myfrwb")` 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": "myfrwb"}, "ref_output": "\u00abm\u00bb\u00abm\u00bb\u00abm\u00bbpiwcxfuepnw", "ref_code": "def main_solution(x):\n    return (func_15('mmm') + func_20('pwxup', 'icfenw'))", "funcname": "main_solution"}
rule