import java.util.Scanner;
public class no0289 {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		char s[] = sc.next().toCharArray();
		int sum = 0;
		for(int i=0; i<s.length; i++){
			if(s[i] >= '0' && s[i] <= '9'){
				sum += Character.getNumericValue(s[i]);
			}
		}
		System.out.println(sum);
	}
}