You are given a code:

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

Can you predict the output of `main_solution("lblp")` 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": "lblp"}, "ref_output": "\u00abyl_\u00bbn\u00ab_bi\u00bb\u00abl\u00bb\u00abp\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_13('yni', '_'))", "funcname": "main_solution"}
rule