You are given a code:

def main_solution(x):
    return func_13(func_5('eufqim', 'seiq'), '-')

Can you predict the output of `main_solution("fillv")` 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": "fillv"}, "ref_output": "s-e-i-q-e-u-f-q-i-m", "ref_code": "def main_solution(x):\n    return func_13(func_5('eufqim', 'seiq'), '-')", "funcname": "main_solution"}
rule