#include <iostream>
#include <algorithm>
using namespace std;
 
int main(){
	int ans = -1;
	for(int i = 1; i <= 12; i++){
		for(int j = 1; j <= 31; j++){
			int j_all = j;
			if(j >= 10){
				j_all -= (to_string(j)[0] - '0') * 9;
			}
			if(i == j_all){
				ans++;
			}
		}
	}
	cout << ans << endl;
}