You are given a code:

def main_solution(x):
    return func_20(func_15('koy'), func_20(x, 'snjf'))

Can you predict the output of `main_solution("nprjkgvca")` 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": "nprjkgvca"}, "ref_output": "\u00abnks\u00bbp\u00abnor\u00bbj\u00abjyf\u00bbkgvca", "ref_code": "def main_solution(x):\n    return func_20(func_15('koy'), func_20(x, 'snjf'))", "funcname": "main_solution"}
rule