You are given a code:

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

Can you predict the output of `main_solution("llutvw")` 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": "llutvw"}, "ref_output": "\u00abgli\u00bbl\u00abllr\u00bbg\u00abiul\u00bbl\u00abrtg\u00bbi\u00ablvl\u00bbr\u00abgwi\u00bbllr", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_1('gillr', 4))", "funcname": "main_solution"}
rule