You are given a code:

def main_solution(x):
    return func_20(func_15(x), func_5('potvwf', 'xjs'))

Can you predict the output of `main_solution("wkqzbser")` 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": "wkqzbser"}, "ref_output": "\u00abxwj\u00bbs\u00abpko\u00bbt\u00abvqw\u00bbf\u00abz\u00bb\u00abb\u00bb\u00abs\u00bb\u00abe\u00bb\u00abr\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_5('potvwf', 'xjs'))", "funcname": "main_solution"}
rule