class ac2
{
    static void Main(string[] args)
    {
        string[] input = Console.ReadLine().Split(' ');
        int N = int.Parse(input[0]);
        int a = int.Parse(input[1]);
        int b = int.Parse(input[2]);
        int c = int.Parse(input[3]);
        int answer = a + c - b;
        if(N == answer)
        {
            Console.WriteLine("Yes");
        }
        else { Console.WriteLine("No");
        }
    }
}