#include <iostream>
using namespace std;
 
const int TEN = 10;
 
int main() {
	int n;
	cin >> n;
	int count = 0;
	while (n > 10) {
		--n;
		if ((n % TEN) * (n / TEN % TEN) == 0) {
			++count;
		}
	}
	while (n >= 0) {
		--n;
		if (n % TEN == 0) {
		++count;
		}
	}
	cout << count;
	return 0;
}