You are given a code:

def main_solution(x):
    return func_20(func_4('mygqt'), func_20('mqgf', 'oibanf'))

Can you predict the output of `main_solution("zxjnkkbl")` 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": "zxjnkkbl"}, "ref_output": "mmyogqqitgbfanf", "ref_code": "def main_solution(x):\n    return func_20(func_4('mygqt'), func_20('mqgf', 'oibanf'))", "funcname": "main_solution"}
rule