You are given a code:

def main_solution(x):
    return func_20(func_15(x), func_20(x, 'uupyup'))

Can you predict the output of `main_solution("subbqozkre")` 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": "subbqozkre"}, "ref_output": "\u00abssu\u00bbu\u00abuub\u00bbp\u00abbby\u00bbq\u00abubo\u00bbp\u00abzqk\u00bbr\u00abeo\u00bb\u00abz\u00bb\u00abk\u00bb\u00abr\u00bb\u00abe\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_20(x, 'uupyup'))", "funcname": "main_solution"}
rule