You are given a code:

def main_solution(x):
    return func_20(func_15('sgtnk'), func_20('eqowis', 'xuos'))

Can you predict the output of `main_solution("yyjm")` 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": "yyjm"}, "ref_output": "\u00abesx\u00bbq\u00abugo\u00bbo\u00abwts\u00bbi\u00absn\u00bb\u00abk\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15('sgtnk'), func_20('eqowis', 'xuos'))", "funcname": "main_solution"}
rule