You are given a code:

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

Can you predict the output of `main_solution("snpwmxfu")` 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": "snpwmxfu"}, "ref_output": "i-x-u-s-n-p-w-m-x-f-u", "ref_code": "def main_solution(x):\n    return func_13(func_5(x, 'ixu'), '-')", "funcname": "main_solution"}
rule