You are given a code:

def main_solution(x):
    return (func_23('nppz', 3) + func_13('lgemud', '_'))

Can you predict the output of `main_solution("mhpmfq")` 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": "mhpmfq"}, "ref_output": "nppz1l_g_e_m_u_d", "ref_code": "def main_solution(x):\n    return (func_23('nppz', 3) + func_13('lgemud', '_'))", "funcname": "main_solution"}
rule