#include "bits/stdc++.h"

using namespace std;


int main() {
	string s;
	cin >> s;
	int res =0;
	for (int i = 0; i < s.length(); i++) {
		if (s[i] == '0') {
			res += 10;
			continue;
		}
		res += s[i] -'0';
	}
	cout << res << endl;

	/*system("pause");*/
}