You are given a code:

def main_solution(x):
    return func_20('vua', 'wpxp')

Can you predict the output of `main_solution("zsvkelrts")` 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": "zsvkelrts"}, "ref_output": "vwupaxp", "ref_code": "def main_solution(x):\n    return func_20('vua', 'wpxp')", "funcname": "main_solution"}
rule