You are given a code:

def main_solution(x):
    return func_20('reksx', x)

Can you predict the output of `main_solution("fbbhbvy")` 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": "fbbhbvy"}, "ref_output": "rfebkbshxbvy", "ref_code": "def main_solution(x):\n    return func_20('reksx', x)", "funcname": "main_solution"}
rule