You are given a code:

def main_solution(x):
    return func_9(('giul' + 'ctxsf'))

Can you predict the output of `main_solution("vzusax")` 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": "vzusax"}, "ref_output": "giulctxsffsxtcluig", "ref_code": "def main_solution(x):\n    return func_9(('giul' + 'ctxsf'))", "funcname": "main_solution"}
rule