import java.util.Scanner;

public class AddAllNum {

    public static void main(String[] args) {
        
        Scanner scanner = new Scanner(System.in);
        
        String s = scanner.next();
        
        int sum = 0;
        
        char c;
        
        for(int i=0;i<s.length();i++){
            
            c = s.charAt(i);
            
            if(Character.isDigit(c)){
                sum += Character.digit(c,10);
            } 
        }
        
        System.out.println(sum);
    }
    
}