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

import static java.lang.System.in;


public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String S = reader.readLine();
        int sum = 0;
        for (int i = 0; i < S.length(); i++) {
            char possibleDigit = S.charAt(i);
            if(Character.isDigit(possibleDigit)) {
                sum += Character.getNumericValue(possibleDigit);
            }
        }
        System.out.println(sum);
    }
}