You are given a code:

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

Can you predict the output of `main_solution("xcoiqpyxxp")` 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": "xcoiqpyxxp"}, "ref_output": "zxvprdxfnx_c_o_i_q_p_y_x_x_p", "ref_code": "def main_solution(x):\n    return (('zxvprd' + 'xfn') + func_13(x, '_'))", "funcname": "main_solution"}
rule