You are given a code:

def main_solution(x):
    return func_9(func_13('xmdbhc', '_'))

Can you predict the output of `main_solution("iiiuvpk")` 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": "iiiuvpk"}, "ref_output": "x_m_d_b_h_cc_h_b_d_m_x", "ref_code": "def main_solution(x):\n    return func_9(func_13('xmdbhc', '_'))", "funcname": "main_solution"}
rule