import java.util.Scanner;

public class No289 {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String str = sc.next();
		int sum = 0;
		
		for(int i = 0;i < str.length();i++) {
			if(Character.isDigit(str.charAt(i))) {
				sum += Integer.parseInt("" + str.charAt(i));
			}
		}
		
		System.out.println(sum);
	}
}