You are given a code:

def main_solution(x):
    return func_20(func_15('rxpmeb'), func_20('vkycif', 'zzxibp'))

Can you predict the output of `main_solution("guk")` 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": "guk"}, "ref_output": "\u00abvrz\u00bbk\u00abzxy\u00bbx\u00abcpi\u00bbi\u00abbmf\u00bbp\u00abe\u00bb\u00abb\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15('rxpmeb'), func_20('vkycif', 'zzxibp'))", "funcname": "main_solution"}
rule