import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

		String str = br.readLine();
		int sum = 0;

		for (int i = 0; i < str.length(); i++) {
			String target = String.valueOf(str.charAt(i));
			sum += target.matches("[0-9]") ? Integer.parseInt(target) : 0;
		}

		System.out.println(sum);

	}

}