You are given a code:

def main_solution(x):
    return (func_13('kghiw', '-') + func_4('pylgwa'))

Can you predict the output of `main_solution("hhbyp")` 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": "hhbyp"}, "ref_output": "k-g-h-i-wpylgwa", "ref_code": "def main_solution(x):\n    return (func_13('kghiw', '-') + func_4('pylgwa'))", "funcname": "main_solution"}
rule