#include <iostream>
#include <algorithm>
#include <vector>
#include<string>

using namespace std;
int main(){
	int s;
	int num,score=0;
	cin >> s;
	for (int i = 0; i < 9; i++) {
		num = s % 10;
		if (num == 0) {
			score += 10;
		} else {
			score += num;
		}
		num /= 10;
	}
	cout << score << endl;
}