You are given a code:

def main_solution(x):
    return (func_11('vtx', 5) + func_13('vmbbh', '-'))

Can you predict the output of `main_solution("xtokb")` 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": "xtokb"}, "ref_output": "aycv-m-b-b-h", "ref_code": "def main_solution(x):\n    return (func_11('vtx', 5) + func_13('vmbbh', '-'))", "funcname": "main_solution"}
rule