You are given a code:

def main_solution(x):
    return func_20('fir', 'fvrxx')

Can you predict the output of `main_solution("xwwhnbas")` 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": "xwwhnbas"}, "ref_output": "ffivrrxx", "ref_code": "def main_solution(x):\n    return func_20('fir', 'fvrxx')", "funcname": "main_solution"}
rule