import java.util.Scanner;

public class sumNum {

	public static void main(String[] args) {
		Scanner sn = new Scanner(System.in);
		String s = sn.next();
		sn.close();
		char[] c = s.toCharArray();
		int num = 0;
		for (int i = 0; i < s.length(); i++) {
			if (c[i] >= '0' && c[i] <= '9') {
				num += Integer.parseInt("" + c[i]);
			} else {
				continue;
			}
		}
		System.out.println(num);

	}

}