You are given a code:

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

Can you predict the output of `main_solution("vegdbii")` 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": "vegdbii"}, "ref_output": "v\u00ab_re\u00bb_\u00abgx_\u00bbd\u00ab_rb\u00bb_\u00abip_\u00bbi\u00abb\u00bb\u00abl\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_13(x, '_'), func_15('rxrpbl'))", "funcname": "main_solution"}
rule