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

int main() {
	int X, count = 0;
	cin >> X;
	for (int i = 0; i < 9; i++) {
		if (X % 10 == 0) count += 10;
		else count += X % 10;
		X /= 10;
	}
	cout << count;
}