import java.util.Scanner;
  
  public class Main {
      public static void main(String[] args) {
          Scanner sc = new Scanner(System.in);
          
          int sum = 0;
          String s = sc.nextLine();
     
          for(int i=0; i<s.length(); i++){
              if(Character.isDigit(s.charAt(i))){
                  sum += Character.getNumericValue(s.charAt(i));
              }else{
                  continue;
              }
          }
          System.out.println(sum);
      }
  }