You are given a code:

def main_solution(x):
    return func_20(func_5('cvqdvr', 'bn'), func_15('qffo'))

Can you predict the output of `main_solution("vrthm")` 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": "vrthm"}, "ref_output": "b\u00abnqc\u00bbv\u00abqfd\u00bbv\u00abrf\u00bb\u00abo\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_5('cvqdvr', 'bn'), func_15('qffo'))", "funcname": "main_solution"}
rule