You are given a code:

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

Can you predict the output of `main_solution("luuqhefsl")` 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": "luuqhefsl"}, "ref_output": "\u00abllh\u00bbu\u00abquu\u00bbt\u00abqul\u00bbh\u00abnqe\u00bbf\u00abshl\u00bb\u00abe\u00bb\u00abf\u00bb\u00abs\u00bb\u00abl\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_20(x, 'hqtln'))", "funcname": "main_solution"}
rule