You are given a code:

def main_solution(x):
    return func_20(func_15('ezhdeq'), func_13('fvmbwp', '_'))

Can you predict the output of `main_solution("mnvptzsfv")` 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": "mnvptzsfv"}, "ref_output": "\u00abfe_\u00bbv\u00ab_zm\u00bb_\u00abbh_\u00bbw\u00ab_dp\u00bb\u00abe\u00bb\u00abq\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15('ezhdeq'), func_13('fvmbwp', '_'))", "funcname": "main_solution"}
rule