You are given a code:

def main_solution(x):
    return func_13(func_20('kzapkt', 'hbwpy'), '_')

Can you predict the output of `main_solution("mkuwqtta")` 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": "mkuwqtta"}, "ref_output": "k_h_z_b_a_w_p_p_k_y_t", "ref_code": "def main_solution(x):\n    return func_13(func_20('kzapkt', 'hbwpy'), '_')", "funcname": "main_solution"}
rule