You are given a code:

def main_solution(x):
    return func_20(('volder' + 'xqzynu'), func_13('mubz', '-'))

Can you predict the output of `main_solution("vmzehpwam")` 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": "vmzehpwam"}, "ref_output": "vmo-lud-ebr-xzqzynu", "ref_code": "def main_solution(x):\n    return func_20(('volder' + 'xqzynu'), func_13('mubz', '-'))", "funcname": "main_solution"}
rule