You are given a code:

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

Can you predict the output of `main_solution("uudl")` 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": "uudl"}, "ref_output": "u\u00abuyd\u00bbl\u00abbgu\u00bbc\u00abvra\u00bb\u00aby\u00bb\u00abv\u00bb\u00abx\u00bb", "ref_code": "def main_solution(x):\n    return func_20((x + 'bucva'), func_15('ygryvx'))", "funcname": "main_solution"}
rule