import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
		char[] array = str.toCharArray();
		int ans = 0;
		for (int i = 0; i < str.length(); i++) {
			if (array[i] >= '0' && array[i] <= '9') {
				ans += Integer.parseInt(String.valueOf(str.charAt(i)));
			}
		}
		System.out.println(ans);
	}
}