You are given a code:

def main_solution(x):
    return ('cujn' + 'gtilbs')

Can you predict the output of `main_solution("ghfi")` 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": "ghfi"}, "ref_output": "cujngtilbs", "ref_code": "def main_solution(x):\n    return ('cujn' + 'gtilbs')", "funcname": "main_solution"}
rule