You are given a code:

def main_solution(x):
    return func_20(func_9(x), func_15('jvtzuh'))

Can you predict the output of `main_solution("fvvhbmnrhb")` 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": "fvvhbmnrhb"}, "ref_output": "f\u00abvjv\u00bbh\u00abbvm\u00bbn\u00abrth\u00bbb\u00abbzh\u00bbr\u00abnum\u00bbb\u00abhhv\u00bbvf", "ref_code": "def main_solution(x):\n    return func_20(func_9(x), func_15('jvtzuh'))", "funcname": "main_solution"}
rule