#include <iostream>

using namespace std;

int main()
{
    string s;
    cin >> s;
    int res = s.size() * (s.size() - 1) / 2 * 9;
    for (size_t i = 0; i < s.size(); i++)
    {
        res += s[i] - '0';
    }
    cout << res;
}