You are given a code:

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

Can you predict the output of `main_solution("slalfobbr")` 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": "slalfobbr"}, "ref_output": "v-s-f-l-e-a-m-l-c-f-o-b-b-r", "ref_code": "def main_solution(x):\n    return func_13(func_20('vfemc', x), '-')", "funcname": "main_solution"}
rule