import java.util.Scanner;
public class Main {
    public static void main (String[] args) {
        Scanner sc = new Scanner(System.in);
        String s = sc.next();
        int ans = 0;
        
     for(int i =0 ; i < s.length(); i++){
         char c = s.charAt(i);
         if(c>='0' && c <= '9'){
             ans += c -48;
         }
     }
     System.out.println(ans);
    }
}