You are given a code:

def main_solution(x):
    return (func_13('ryzub', '-') + func_15('fcj'))

Can you predict the output of `main_solution("kdfamvt")` 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": "kdfamvt"}, "ref_output": "r-y-z-u-b\u00abf\u00bb\u00abc\u00bb\u00abj\u00bb", "ref_code": "def main_solution(x):\n    return (func_13('ryzub', '-') + func_15('fcj'))", "funcname": "main_solution"}
rule