You are given a code:

def main_solution(x):
    return func_20(func_17(x), func_15('xpkrs'))

Can you predict the output of `main_solution("cisxspdn")` 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": "cisxspdn"}, "ref_output": "n\u00abdxp\u00bbs\u00abxps\u00bbi\u00abck\u00bb\u00abr\u00bb\u00abs\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_17(x), func_15('xpkrs'))", "funcname": "main_solution"}
rule