import java.util.Scanner;

public class NumberAdd {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		String S =  scan.next();
		int c = 0;
		int f;
		for(int i=0;i<S.length();i++){
			try{
				char x = S.charAt(i);
				String y = Character.toString(x);
				f = Integer.parseInt(y);
			}catch(Exception e){
			 continue;
			}
			c += f;
		}
		System.out.println(c);
	}

}