You are given a code:

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

Can you predict the output of `main_solution("fuqnigxsex")` 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": "fuqnigxsex"}, "ref_output": "\u00abxf_\u00bbs\u00ab_ur\u00bb_\u00abbq_\u00bbq\u00ab_nj\u00bb\u00abi\u00bb\u00abg\u00bb\u00abx\u00bb\u00abs\u00bb\u00abe\u00bb\u00abx\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_13('xsrbqj', '_'))", "funcname": "main_solution"}
rule