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