using System.Numerics;

public class Program
{
    public static void Main()
    {
        
        //int num = int.Parse(Console.ReadLine() ?? string.Empty);
        string[] str = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        //string str = Console.ReadLine() ?? string.Empty;

        int s = int.Parse(str[0]);
        int e = int.Parse(str[1]);
        if(s > 25||e < 23)
        {
            Console.WriteLine(3);
            return;
        }
        else if(s <= 23 && e >= 25)
        {
            Console.WriteLine(0);
            return;
        }
        int count = 3;
            for (int i = s; i <= e; i++)
            {
            if(i == 23 || i == 24 || i == 25)
            {
                count--;
            }
            }
            Console.WriteLine(count);

    }
}