You are given a code:

def main_solution(x):
    return func_20((x + x), func_15('jmpffu'))

Can you predict the output of `main_solution("ruuu")` 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": "ruuu"}, "ref_output": "r\u00abuju\u00bbu\u00abrmu\u00bbu\u00abup\u00bb\u00abf\u00bb\u00abf\u00bb\u00abu\u00bb", "ref_code": "def main_solution(x):\n    return func_20((x + x), func_15('jmpffu'))", "funcname": "main_solution"}
rule