#include <iostream>
using namespace std;
int main() {
    long long n;
    cin >> n;
    int a = 0;
    if (n >= 1){
        for (int i = 1; i <= n; i++)
        {

            if (n / 10 != 0)
                a++;
            else if (n / 10 == 0)
                break;
            n /= 10;
        }
    cout << (a + 2) * 9;
}
    return 0;
}