You are given a code:

def main_solution(x):
    return func_20(func_15(x), func_13('slnndf', '-'))

Can you predict the output of `main_solution("zibg")` 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": "zibg"}, "ref_output": "\u00absz-\u00bbl\u00ab-in\u00bb-\u00abnb-\u00bbd\u00ab-gf\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_13('slnndf', '-'))", "funcname": "main_solution"}
rule