You are given a code:

def main_solution(x):
    return func_13(func_20('vlobi', 'jonba'), '-')

Can you predict the output of `main_solution("jjd")` 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": "jjd"}, "ref_output": "v-j-l-o-o-n-b-b-i-a", "ref_code": "def main_solution(x):\n    return func_13(func_20('vlobi', 'jonba'), '-')", "funcname": "main_solution"}
rule