You are given a code:

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

Can you predict the output of `main_solution("zqhskftni")` 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": "zqhskftni"}, "ref_output": "\u00abmz-\u00bbh\u00ab-qe\u00bb-\u00abeh-\u00bbr\u00ab-sz\u00bb\u00abk\u00bb\u00abf\u00bb\u00abt\u00bb\u00abn\u00bb\u00abi\u00bb", "ref_code": "def main_solution(x):\n    return func_20(func_15(x), func_13('mheerz', '-'))", "funcname": "main_solution"}
rule