You are given a code:

def main_solution(x):
    return func_5(func_13(x, '_'), 'zme')

Can you predict the output of `main_solution("yvwkdmoqgz")` 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": "yvwkdmoqgz"}, "ref_output": "zmey_v_w_k_d_m_o_q_g_z", "ref_code": "def main_solution(x):\n    return func_5(func_13(x, '_'), 'zme')", "funcname": "main_solution"}
rule