using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static long[] NList => ReadLine().Split().Select(long.Parse).ToArray();
    public static void Main()
    {
        Solve();
    }
    static void Solve()
    {
        var c = NList;
        var (l, r) = (c[0], c[1]);
        var sq = new bool[r - l + 1];
        for (var x = 2L; x <= 1_000_000; ++x)
        {
            var begin = (x * x - l) % (x * x);
            if (begin < 0) begin += x * x;
            for (var i = begin; i < sq.Length; i += x * x) sq[i] = true;
        }
        for (var k = 1L; k < 1_000_000; ++k)
        {
            var x = Sqrt(r / k);
            if (x <= 1_000_000) break;
            if (l <= k * x * x && k * x * x <= r) sq[k * x * x - l] = true;
        }
        WriteLine(sq.Count(f => !f));
    }
    static long Sqrt(long n)
    {
        var ans = (long)Math.Sqrt(n);
        if ((ans + 1) * (ans + 1) <= n) return ans + 1;
        return ans;
    }
}