You are given a code:

def main_solution(x):
    return func_20(func_15(x), func_5(x, 'flep'))

Can you predict the output of `main_solution("lzbtb")` 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": "lzbtb"}, "ref_output": "\u00abfll\u00bbe\u00abpzl\u00bbz\u00abbbt\u00bbb\u00abt\u00bb\u00abb\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_5(x, 'flep'))", "funcname": "main_solution"}
rule