You are given a code:

def main_solution(x):
    return func_4(func_5('tbo', 'mdgb'))

Can you predict the output of `main_solution("qtlau")` 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": "qtlau"}, "ref_output": "mdgbtbo", "ref_code": "def main_solution(x):\n    return func_4(func_5('tbo', 'mdgb'))", "funcname": "main_solution"}
rule