You are given a code:

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

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