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

public class No00000656_Main {
	static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	public static void main(String[] args) throws IOException {
		String s = br.readLine();
		int c = 0;
		for(int i = 0; i < s.length(); i++) {
			int t = s.charAt(i) - '0';
			if(t == 0) c += 10;
			else c += t;
		}
		System.out.println(c);
	}
}