import java.util.Scanner;
public class Main{
	public static void main(String[] args) {
		//System.out.println("半角英数字の文字列");
		Scanner scanner = new Scanner(System.in);
		String str = scanner.next();
		scanner.close();
		int sum = 0;
		for(int i = 0; i < str.length(); i++) {
			String s = str.substring(i,i+1);
			if(s.matches("[0-9]{1}")) {
				sum += Integer.parseInt(s);
			}
		}
		System.out.println(sum);
	}
}