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

namespace yukicoderTest
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] str = Console.ReadLine().Split(' ');
            int s = int.Parse(str[0]);
            int e = int.Parse(str[1]);
            int day = 3;
            for(int i=s;i<=e;i++)
            {
                if(i==23||i==24||i==25)
                {
                    day--;
                }
            }
            Console.WriteLine(day);
        }
    }
}