You are given a code:

def main_solution(x):
    return func_13(('rmxfnv' + 'tqzxhw'), '_')

Can you predict the output of `main_solution("hwc")` 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": "hwc"}, "ref_output": "r_m_x_f_n_v_t_q_z_x_h_w", "ref_code": "def main_solution(x):\n    return func_13(('rmxfnv' + 'tqzxhw'), '_')", "funcname": "main_solution"}
rule