You are given a code:

def main_solution(x):
    return func_20(func_15(x), func_5(x, 'iwz'))

Can you predict the output of `main_solution("mbjphumjuv")` 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": "mbjphumjuv"}, "ref_output": "\u00abimw\u00bbz\u00abmbb\u00bbj\u00abpjh\u00bbu\u00abmpj\u00bbu\u00abvh\u00bb\u00abu\u00bb\u00abm\u00bb\u00abj\u00bb\u00abu\u00bb\u00abv\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_5(x, 'iwz'))", "funcname": "main_solution"}
rule