You are given a code:

def main_solution(x):
    return ('airrdn' + 'gbnxgp')

Can you predict the output of `main_solution("sufmu")` 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": "sufmu"}, "ref_output": "airrdngbnxgp", "ref_code": "def main_solution(x):\n    return ('airrdn' + 'gbnxgp')", "funcname": "main_solution"}
rule