You are given a code:

def main_solution(x):
    return func_20(func_15('adm'), ('rbthdn' + 'befa'))

Can you predict the output of `main_solution("zyigfqtes")` 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": "zyigfqtes"}, "ref_output": "\u00abrab\u00bbt\u00abhdd\u00bbn\u00abbme\u00bbfa", "ref_code": "def main_solution(x):\n    return func_20(func_15('adm'), ('rbthdn' + 'befa'))", "funcname": "main_solution"}
rule