You are given a code:

def main_solution(x):
    return func_13(func_20('szitr', x), '_')

Can you predict the output of `main_solution("qjbkbelrtd")` 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": "qjbkbelrtd"}, "ref_output": "s_q_z_j_i_b_t_k_r_b_e_l_r_t_d", "ref_code": "def main_solution(x):\n    return func_13(func_20('szitr', x), '_')", "funcname": "main_solution"}
rule