using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace yukicoder_188
{
    class Program
    {
        static void Main(string[] args)
        {
            int day = 0;
            for (int m = 1; m <= 12; m++)
            {
                if (m == 1 || m == 3 || m == 5 || m == 7 || m == 8 || m == 10 || m == 12)
                {
                    for(int d = 1; d <= 31; d++)
                    {
                        if (m == d % 10 + d / 10)
                        {
                            day++;
                        }
                    }
                }
                else if(m == 2)
                {
                    for (int d = 1; d <= 28; d++) 
                    {
                        if (m == d % 10 + d / 10)
                        {
                            day++;
                        }
                    }
                }
                else
                {
                    for (int d = 1; d <=30; d++) 
                    {
                        if (m == d % 10 + d / 10)
                        {
                            day++;
                        }
                    }
                }
            }
            Console.WriteLine(day);
            Console.ReadLine();
        }
    }
}