You are given a code:

def main_solution(x):
    return func_20(func_15('hdx'), func_20('rukpx', 'yri'))

Can you predict the output of `main_solution("ppjwu")` 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": "ppjwu"}, "ref_output": "\u00abrhy\u00bbu\u00abrdk\u00bbi\u00abpxx\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15('hdx'), func_20('rukpx', 'yri'))", "funcname": "main_solution"}
rule