using System;
using System.Linq;
using System.Collections.Generic;
using System.Text.RegularExpressions;


class Program
{
    static void Main()
    {
        var month = new List<int>() { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 };

        var _ans = 0;

        for (var i = 0; month.Count > i; i++)
        {
            foreach (var j in Enumerable.Range(1, 31))
            {
                var s = j.ToString();
                if (s.Length == 1)
                {
                    if (j == month[i]) _ans++;
                }
                else
                {
                    int a = (int)char.GetNumericValue(s[0]);
                    int b = (int)char.GetNumericValue(s[1]);
                    if (a + b == month[i]) _ans++;
                }
            }
        }
        Console.WriteLine(_ans - 1);
    }
}