You are given a code:

def main_solution(x):
    return (func_13(x, '_') + func_13('zfsdd', '|'))

Can you predict the output of `main_solution("ilvvbvi")` 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": "ilvvbvi"}, "ref_output": "i_l_v_v_b_v_iz|f|s|d|d", "ref_code": "def main_solution(x):\n    return (func_13(x, '_') + func_13('zfsdd', '|'))", "funcname": "main_solution"}
rule