You are given a code:

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

Can you predict the output of `main_solution("revkxfoj")` 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": "revkxfoj"}, "ref_output": "r-e-v-k-x-f-o-j\u00abf\u00bb\u00abq\u00bb\u00abf\u00bb\u00abv\u00bb\u00abj\u00bb\u00abl\u00bb", "ref_code": "def main_solution(x):\n    return (func_13(x, '-') + func_15('fqfvjl'))", "funcname": "main_solution"}
rule