You are given a code:

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

Can you predict the output of `main_solution("ynu")` 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": "ynu"}, "ref_output": "y\u00abyxn\u00bbn\u00abuhu\u00bb\u00abs\u00bb\u00abi\u00bb\u00abv\u00bb\u00aby\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_20(x, x), func_15('xhsivy'))", "funcname": "main_solution"}
rule