You are given a code:

def main_solution(x):
    return func_4('qxqbkh')

Can you predict the output of `main_solution("vmzww")` 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": "vmzww"}, "ref_output": "qxqbkh", "ref_code": "def main_solution(x):\n    return func_4('qxqbkh')", "funcname": "main_solution"}
rule