def main():
    N, L = map(int, input().split())

    if (N - 1) * 2 > L:
        print(0)
        return

    n = L // (N - 1)
    lst = erastosthenes(n)
    cnt = L - (N - 1) * 2 + 1
    for i in range(3, n + 1, 2):
        if lst[i]:
            cnt += L - (N - 1) * i + 1
    print(cnt)

def erastosthenes(n):
    prime = [0, 1] * ((n + 1) // 2)
    if not n % 2:
        prime += [0]
    prime[1], prime[2] = 0, 1

    sqrt = n ** 0.5
    i = 3
    while i <= sqrt:
        for j in range(i ** 2, n + 1, i):
            prime[j] = 0
        i += 2
    return prime

main()