You are given a code:

def main_solution(x):
    return func_20(func_20('khx', 'snzz'), func_20('vsykmy', 'hpckbx'))

Can you predict the output of `main_solution("udckj")` 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": "udckj"}, "ref_output": "kvshhsnpxyzczkkmbyx", "ref_code": "def main_solution(x):\n    return func_20(func_20('khx', 'snzz'), func_20('vsykmy', 'hpckbx'))", "funcname": "main_solution"}
rule