using System;
class Sample
{
    public static void Main()
    {
        int count = 0;
        int num;
        for(int i = 1; i <= 12; i++)
        {
            switch(i){
                case (2):
                    num = 28;
                    break;
                case (4):
                    num = 30;
                    break;
                case (6):
                    num = 30;
                    break;
                case (9):
                    num = 30;
                    break;
                case (11):
                    num = 30;
                    break;
                default:
                    num = 31;
                    break;
            }
            for(int j = 1; j <= num; j++)
            {
                int month = j / 10;
                int day = j % 10;
                if (i == month + day)
                {
                    count++;
                }
            }
            
        }
        Console.WriteLine(count);
    }
}