import java.util.*;

public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String line = sc.nextLine();
        int total = 0;
        for (int i = 0; i<line.length(); i++){
            char c = line.charAt(i);
            if(48 <= c && c <= 57){
                total += Character.getNumericValue(c);
            }
        }
        System.out.println(total);
    }
}