You are given a code:

def main_solution(x):
    return func_20(func_1(x, 3), func_15('frbm'))

Can you predict the output of `main_solution("hkpsk")` 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": "hkpsk"}, "ref_output": "h\u00abkfp\u00bbs\u00abkrh\u00bbk\u00abpbs\u00bbk\u00abhmk\u00bbpsk", "ref_code": "def main_solution(x):\n    return func_20(func_1(x, 3), func_15('frbm'))", "funcname": "main_solution"}
rule