You are given a code:

def main_solution(x):
    return func_20(func_23('grxexk', 2), func_15(x))

Can you predict the output of `main_solution("rttunlgj")` 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": "rttunlgj"}, "ref_output": "g\u00abrrx\u00bbe\u00abxtk\u00bb1\u00abt\u00bb\u00abu\u00bb\u00abn\u00bb\u00abl\u00bb\u00abg\u00bb\u00abj\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_23('grxexk', 2), func_15(x))", "funcname": "main_solution"}
rule