You are given a code:

def main_solution(x):
    return func_20(func_1('dtfna', 4), func_15('iwn'))

Can you predict the output of `main_solution("qlvft")` 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": "qlvft"}, "ref_output": "d\u00abtif\u00bbn\u00abawd\u00bbt\u00abfnn\u00bbadtfnadtfna", "ref_code": "def main_solution(x):\n    return func_20(func_1('dtfna', 4), func_15('iwn'))", "funcname": "main_solution"}
rule