You are given a code:

def main_solution(x):
    return (('agv' + 'eswtvw') + func_20('xxuct', 'ati'))

Can you predict the output of `main_solution("hstdkb")` 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": "hstdkb"}, "ref_output": "agveswtvwxaxtuict", "ref_code": "def main_solution(x):\n    return (('agv' + 'eswtvw') + func_20('xxuct', 'ati'))", "funcname": "main_solution"}
rule