public class Main{
  public static void main(String[] args){
    String[] line = new java.util.Scanner(System.in).next().split("");
    int sum = 0;
    for(int i=0;i<line.length;i++){
      sum += Integer.parseInt(line[i].replaceAll("[^0-9]","0"));
    }
    System.out.println(sum);
  }
}