You are given a code:

def main_solution(x):
    return (func_15('uokhp') + func_13('nlbmji', '_'))

Can you predict the output of `main_solution("kutqzvnjgd")` 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": "kutqzvnjgd"}, "ref_output": "\u00abu\u00bb\u00abo\u00bb\u00abk\u00bb\u00abh\u00bb\u00abp\u00bbn_l_b_m_j_i", "ref_code": "def main_solution(x):\n    return (func_15('uokhp') + func_13('nlbmji', '_'))", "funcname": "main_solution"}
rule