import java.util.Scanner;

public class A000163 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String str = sc.nextLine();
		sc.close();

		int r = 0;
		for(char c:str.toCharArray()) {
			int a = Character.getNumericValue(c);
			if(0<a&&a<10)r+=a;
		}
		System.out.println(r);
	}

}