You are given a code:

def main_solution(x):
    return func_20(func_1('hubaa', 3), func_15('axjr'))

Can you predict the output of `main_solution("zud")` 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": "zud"}, "ref_output": "h\u00abuab\u00bba\u00abaxh\u00bbu\u00abbja\u00bba\u00abhru\u00bbbaa", "ref_code": "def main_solution(x):\n    return func_20(func_1('hubaa', 3), func_15('axjr'))", "funcname": "main_solution"}
rule