You are given a code:

def main_solution(x):
    return func_20(func_15('usos'), ('iqntsr' + x))

Can you predict the output of `main_solution("bvgkyfoqf")` 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": "bvgkyfoqf"}, "ref_output": "\u00abiuq\u00bbn\u00abtss\u00bbr\u00abbov\u00bbg\u00abksy\u00bbfoqf", "ref_code": "def main_solution(x):\n    return func_20(func_15('usos'), ('iqntsr' + x))", "funcname": "main_solution"}
rule