You are given a code:

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

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