You are given a code:

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

Can you predict the output of `main_solution("mjhsufmf")` 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": "mjhsufmf"}, "ref_output": "t_k_f_p_b_q_l_c_y_e_h", "ref_code": "def main_solution(x):\n    return func_13(('tkfpbq' + 'lcyeh'), '_')", "funcname": "main_solution"}
rule