You are given a code:

def main_solution(x):
    return func_9('aopb')

Can you predict the output of `main_solution("jupvkt")` 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": "jupvkt"}, "ref_output": "aopbbpoa", "ref_code": "def main_solution(x):\n    return func_9('aopb')", "funcname": "main_solution"}
rule