You are given a code:

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

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