You are given a code:

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

Can you predict the output of `main_solution("hbkwc")` 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": "hbkwc"}, "ref_output": "\u00ab\u00abhi\u00bb\u00bb\u00ab\u00abbq\u00bb\u00bb\u00ab\u00abkv\u00bb\u00bb\u00ab\u00abwo\u00bb\u00bb\u00ab\u00abcy\u00bb\u00bb\u00abu\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_15('iqvoyu'))", "funcname": "main_solution"}
rule