You are given a code:

def main_solution(x):
    return func_20(func_13('ygop', '-'), func_17('znemb'))

Can you predict the output of `main_solution("oftzeql")` 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": "oftzeql"}, "ref_output": "yb-mge-noz-p", "ref_code": "def main_solution(x):\n    return func_20(func_13('ygop', '-'), func_17('znemb'))", "funcname": "main_solution"}
rule