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

public class No00000289_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++) {
			char c = str.charAt(i);
			if('0' <= c && c <= '9') sum +=Integer.parseInt(String.valueOf(c));
		}
		System.out.println(sum);
	}
}