You are given a code:

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

Can you predict the output of `main_solution("reitpw")` 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": "reitpw"}, "ref_output": "e_x_r_i_h_r_e_i_t_p_w", "ref_code": "def main_solution(x):\n    return func_13(('exrih' + x), '_')", "funcname": "main_solution"}
rule