You are given a code:

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

Can you predict the output of `main_solution("ztbxclkrfh")` 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": "ztbxclkrfh"}, "ref_output": "\u00abszz\u00bbq\u00abttx\u00bbb\u00abxbc\u00bbl\u00abkxr\u00bbf\u00abhc\u00bb\u00abl\u00bb\u00abk\u00bb\u00abr\u00bb\u00abf\u00bb\u00abh\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_20('sqx', x))", "funcname": "main_solution"}
rule