You are given a code:

def main_solution(x):
    return (func_23('qjf', 1) + func_13(x, '_'))

Can you predict the output of `main_solution("uypphvparp")` 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": "uypphvparp"}, "ref_output": "qjf1u_y_p_p_h_v_p_a_r_p", "ref_code": "def main_solution(x):\n    return (func_23('qjf', 1) + func_13(x, '_'))", "funcname": "main_solution"}
rule