using System;

public class Program {
	public static void Main(string[] args) {
		char[] chars = Console.ReadLine().ToCharArray();
		int sum = 0;
		for (int i = 0; i < chars.Length; i++) {
			if (char.IsDigit(chars[i])) {
				sum += int.Parse(chars[i].ToString());
			}
		}
		Console.WriteLine(sum);
	}
}