You are given a code:

def main_solution(x):
    return func_13(('pgsnwh' + 'tmxjr'), '_')

Can you predict the output of `main_solution("qkzbrezxm")` 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": "qkzbrezxm"}, "ref_output": "p_g_s_n_w_h_t_m_x_j_r", "ref_code": "def main_solution(x):\n    return func_13(('pgsnwh' + 'tmxjr'), '_')", "funcname": "main_solution"}
rule