You are given a code:

def main_solution(x):
    return func_20(func_15('wkciao'), func_20('gtpvpn', x))

Can you predict the output of `main_solution("nbtfinhs")` 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": "nbtfinhs"}, "ref_output": "\u00abgwn\u00bbt\u00abbkp\u00bbt\u00abvcf\u00bbp\u00abiin\u00bbn\u00abhas\u00bb\u00abo\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15('wkciao'), func_20('gtpvpn', x))", "funcname": "main_solution"}
rule