import java.util.Scanner;

public class Main{
	public static void main(String[] args){
        Scanner sc=new Scanner(System.in);
        while(sc.hasNext()){
        	String s=sc.next();
        	int res=0;
        	for(int i=0;i<s.length();i++) if(s.charAt(i)-'0'>=0 && s.charAt(i)-'0'<=9) res+=s.charAt(i)-'0';
        	System.out.println(res);
        }
    }
}