You are given a code:

def main_solution(x):
    return func_20(func_15('ozy'), func_4('efsb'))

Can you predict the output of `main_solution("oyzcvq")` 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": "oyzcvq"}, "ref_output": "\u00abeof\u00bbs\u00abbz\u00bb\u00aby\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15('ozy'), func_4('efsb'))", "funcname": "main_solution"}
rule