You are given a code:

def main_solution(x):
    return func_20(func_15(x), func_20('uov', x))

Can you predict the output of `main_solution("vztidat")` 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": "vztidat"}, "ref_output": "\u00abuvv\u00bbo\u00abzzv\u00bbt\u00abitd\u00bba\u00abti\u00bb\u00abd\u00bb\u00aba\u00bb\u00abt\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_20('uov', x))", "funcname": "main_solution"}
rule