You are given a code:

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

Can you predict the output of `main_solution("hftfrwd")` 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": "hftfrwd"}, "ref_output": "s\u00abkhz\u00bbu\u00abhff\u00bbt\u00abftr\u00bbw\u00abdf\u00bb\u00abr\u00bb\u00abw\u00bb\u00abd\u00bb", "ref_code": "def main_solution(x):\n    return func_20(('skzu' + x), func_15(x))", "funcname": "main_solution"}
rule