You are given a code:

def main_solution(x):
    return func_20(func_20(x, 'nvz'), func_15(x))

Can you predict the output of `main_solution("kprvbicn")` 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": "kprvbicn"}, "ref_output": "k\u00abnkp\u00bbv\u00abrpz\u00bbv\u00abbri\u00bbc\u00abnv\u00bb\u00abb\u00bb\u00abi\u00bb\u00abc\u00bb\u00abn\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_20(x, 'nvz'), func_15(x))", "funcname": "main_solution"}
rule