import java.util.Scanner;


public class Main_yukicoder289 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        char[] s = sc.next().toCharArray();
        int ret = 0;
        for (int i = 0; i < s.length; i++) {
        	if (s[i] >= '0' && s[i] <= '9') {
        		ret += s[i] - '0';
        	}
        }

        System.out.println(ret);

        sc.close();
    }
}