You are given a code:

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

Can you predict the output of `main_solution("muq")` 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": "muq"}, "ref_output": "\u00absm_\u00bbl\u00ab_ub\u00bb_\u00abyq_\u00bbt_l", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_13('slbytl', '_'))", "funcname": "main_solution"}
rule