You are given a code:

def main_solution(x):
    return ('dvue' + 'rzrn')

Can you predict the output of `main_solution("fvmervpio")` 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": "fvmervpio"}, "ref_output": "dvuerzrn", "ref_code": "def main_solution(x):\n    return ('dvue' + 'rzrn')", "funcname": "main_solution"}
rule