#nullable enable

#region
var (_input, _iter) = (Array.Empty<string>(), 0);
T I<T>() where T : IParsable<T>
{
    while (_iter >= _input.Length) (_input, _iter) = (Console.ReadLine()!.Split(' '), 0);
    return T.Parse(_input[_iter++], null);
}
#endregion

var primes = new Prime(101).Primes;

var a = I<long>();
var b = I<long>();

var ans = 0L;
foreach (long p in primes)
{
    if (p < a || b < p) continue;
    ans += p * p * p - p * p + p + 1;
}
Console.WriteLine(ans);

class Prime
{
    public readonly int[] Sieve, Primes;

    public Prime(int n)
    {
        if (n <= 3) n = 3;
        var sieve = new int[n + 1];
        var (d, i) = (2, 5);
        var primes = new List<int>(){ 2, 3 };
        sieve[1] = 1;
        for (var j = 2; j <= n; j += 2) sieve[j] = 2;
        for (var j = 3; j <= n; j += 3) sieve[j] = 3;
        while (i <= n)
        {
            if (sieve[i] == 0)
            {
                primes.Add(i);
                for (var j = i; j <= n; j += i) sieve[j] = i;
            }
            i += d;
            d ^= 6;
        }
        (Sieve, Primes) = (sieve, primes.ToArray());
    }
}