You are given a code:

def main_solution(x):
    return func_20(('hpzix' + 'tkq'), func_13('owf', '_'))

Can you predict the output of `main_solution("rbler")` 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": "rbler"}, "ref_output": "hop_zwi_xftkq", "ref_code": "def main_solution(x):\n    return func_20(('hpzix' + 'tkq'), func_13('owf', '_'))", "funcname": "main_solution"}
rule