import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.lang.Character;
public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader stdReader =new BufferedReader(new InputStreamReader(System.in));
		String line = stdReader.readLine();
		int ans = 0;
		for(int i=0;i<line.length();i++){
			if(line.charAt(i)>='0' && line.charAt(i) <= '9'){
				ans += Integer.parseInt(""+line.charAt(i));
			}
		}
		System.out.println(ans);
	}
}