#include <iostream>
#include <string>
using namespace std;

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

    int ans = 0;
    for(int i = 0; i < s.length(); i++){
        if(s[i] == '0') ans += 10;
        else ans += s[i] - '0';
    }

    cout << ans << endl;

    return 0;
}