using System;
using System.IO;

public class Test
{
	public static void Main()
	{
                string fileName = "Filename.OUT";
                string seed = "6F9619FF-8B86-D011-B42D-00C04FC964FF";
                string input = fileName + seed;
                Console.WriteLine(seed.Length);
                Console.WriteLine(Guid.NewGuid().ToString().Length);
                string result = input.Substring(0, input.Length - seed.Length);
                Console.WriteLine(result);
                var file = new FileInfo(result);
                Console.WriteLine(file.Extension);
                
	}
}