#include <bits/stdc++.h>
using namespace std;

int main() {
	string s;
	cin >> s;

	int sum = 0;
	for (int i = 0; i < s.size(); i++) {
		int n = (int)s.at(i) - '0';
		if (!n) n = 10;
		sum += n;
	}

	cout << sum << endl;
}