#include <iostream>

using namespace std;

int main(void)
{
        long long x;
        cin >> x;

        long long t = x;
        long long sum = 0;

        if (x == 0)
        {
                cout << 1 << endl;
                return 0;
        }
        else if (x <= 9)
        {
                cout << (x + 1) << endl;
                return 0;
        }
        else if (x == 10)
        {
                cout << 10 << endl;
                return 0;
        }

        int k = 0;
        long long num = 0;
        while (x > 10)
        {
                num++;
                sum += 10;
                k = x % 10;
                x = x / 10;
        }

        long long xt = x;
        while (num > 0)
        {
                xt *= 10;
                xt += x;
                num--;
        }

        long long suman = sum + x;
        if (xt > t) suman--;
        cout << suman << endl;

        return 0;
}