You are given a code:

def main_solution(x):
    return func_20(func_15('vcf'), func_20('kmpd', x))

Can you predict the output of `main_solution("mvmhukb")` 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": "mvmhukb"}, "ref_output": "\u00abkvm\u00bbm\u00abvcp\u00bbm\u00abdfh\u00bbukb", "ref_code": "def main_solution(x):\n    return func_20(func_15('vcf'), func_20('kmpd', x))", "funcname": "main_solution"}
rule