You are given a code:

def main_solution(x):
    return func_20('fcopzb', 'exuj')

Can you predict the output of `main_solution("yqbbyckzr")` 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": "yqbbyckzr"}, "ref_output": "fecxoupjzb", "ref_code": "def main_solution(x):\n    return func_20('fcopzb', 'exuj')", "funcname": "main_solution"}
rule