You are given a code:

def main_solution(x):
    return func_5(func_13(x, '_'), 'qtjt')

Can you predict the output of `main_solution("cdbuiyltu")` 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": "cdbuiyltu"}, "ref_output": "qtjtc_d_b_u_i_y_l_t_u", "ref_code": "def main_solution(x):\n    return func_5(func_13(x, '_'), 'qtjt')", "funcname": "main_solution"}
rule