You are given a code:

def main_solution(x):
    return func_20(func_13(x, '_'), func_15('saibp'))

Can you predict the output of `main_solution("yubshsvl")` 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": "yubshsvl"}, "ref_output": "y\u00ab_su\u00bb_\u00abba_\u00bbs\u00ab_ih\u00bb_\u00absb_\u00bbv\u00ab_pl\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_13(x, '_'), func_15('saibp'))", "funcname": "main_solution"}
rule