You are given a code:

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

Can you predict the output of `main_solution("tuko")` 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": "tuko"}, "ref_output": "\u00abltv\u00bbu\u00abyuw\u00bbm\u00ablkv\u00bbu\u00abyow\u00bbmlvuywmlvuywm", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_1('lvuywm', 4))", "funcname": "main_solution"}
rule