You are given a code:

def main_solution(x):
    return func_20(func_22(x), func_15('yfae'))

Can you predict the output of `main_solution("rsdllvugub")` 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": "rsdllvugub"}, "ref_output": "r\u00absyd\u00bbl\u00ablfv\u00bbu\u00abgau\u00bbb\u00abe\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_22(x), func_15('yfae'))", "funcname": "main_solution"}
rule