#include <iostream>
#include <string>

using namespace std;

int main()
{
    string input; cin >> input;
    int sum=0;
    for (string::iterator it=input.begin(); it!=input.end(); ++it){
    	int num = (int)(*it) - 48;
	if (num == 0){
		sum += 10;
	} else{
		sum += num;
	}	
    }
    cout << sum << endl;
    return 0;
}