You are given a code:

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

Can you predict the output of `main_solution("lzefzb")` 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": "lzefzb"}, "ref_output": "\u00abvly\u00bby\u00ablzz\u00bbe\u00abfez\u00bbb\u00abf\u00bb\u00abz\u00bb\u00abb\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_5(x, 'vyy'))", "funcname": "main_solution"}
rule