import java.util.Scanner;

public class No289 {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		String line = sc.next();

		int ans = 0;

		for(int i = 0; i < line.length(); i++){
			char ch = line.charAt(i);
			if(Character.isDigit(ch)){
				ans += Integer.parseInt(String.valueOf(ch));
			}
		}
		System.out.println(ans);
	}

}