using System;

namespace No289
{
	class MainClass
	{
		public static void Main (string[] args)
		{
			var s = Console.ReadLine ();
			int sum = 0;
			for (int i = 0; i < s.Length; i++) {
				if (char.IsDigit (s [i])) {
					sum += (int)(s [i] - '0');					
				}
			}
			Console.WriteLine (sum.ToString ());
					
		}
	}
}