You are given a code:

def main_solution(x):
    return func_22(func_20('fdyz', 'mpvz'))

Can you predict the output of `main_solution("vpbjz")` 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": "vpbjz"}, "ref_output": "fmdpyvzz", "ref_code": "def main_solution(x):\n    return func_22(func_20('fdyz', 'mpvz'))", "funcname": "main_solution"}
rule