You are given a code:

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

Can you predict the output of `main_solution("igprkzy")` 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": "igprkzy"}, "ref_output": "\u00abiv-\u00bbg\u00ab-mp\u00bb-\u00abrv-\u00bbk\u00ab-oz\u00bb-\u00abyj\u00bb\u00abu\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15('vmvoju'), func_13(x, '-'))", "funcname": "main_solution"}
rule