import java .util.Scanner;
public class Yukicoder {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);
		String s = sc.next();

		char[] array = s.toCharArray();
		int sum = 0;
		for (int i = 0; i < s.length(); i++) {
			if (array[i] >= '0' && array[i] <= '9') {
				sum += Integer.parseInt("" + array[i]);
			}
		}
		System.out.print(sum);

	}

}