You are given a code:

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

Can you predict the output of `main_solution("wgrfkrkbks")` 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": "wgrfkrkbks"}, "ref_output": "j\u00abnwl\u00bbd\u00abvgu\u00bbw\u00abgrr\u00bbf\u00abkfr\u00bbk\u00abbkk\u00bbs\u00abr\u00bb\u00abk\u00bb\u00abb\u00bb\u00abk\u00bb\u00abs\u00bb", "ref_code": "def main_solution(x):\n    return func_20(('jnldvu' + x), func_15(x))", "funcname": "main_solution"}
rule