#include <iostream>
using namespace std;
/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(void) {
	int sum;
	for(int i=1; i<=12; i++)
	{
		for(int j=1; j<=30; j++)
		{
			if(i == j/10 + j%10)
			{
				sum += 1;
			}
			
			else
			{
				sum += 0;
			}
		}
	}
	cout<<sum<<endl;
	return 0;
}