mod = 1000000007
eps = 10**-9


def main():
    import sys
    from math import sqrt
    input = sys.stdin.readline

    N = 10 ** 6
    L, R = map(int, input().split())
    A = list(range(L, R+1))
    for d in range(2, N+1):
        xl = (L - 1) // d + 1
        xr = R // d
        for x in range(xl, xr + 1):
            m = A[d * x - L]
            if m != -1:
                if m % (d**2) == 0:
                    A[d*x - L] = -1
                else:
                    if m % d == 0:
                        A[d * x - L] //= d
    ans = 0
    for m_ in range(L, R+1):
        if A[m_ - L] == -1:
            continue
        ans += 1
        m = A[m_ - L]
        if m != 1:
            mm = int(sqrt(m))
            for j in range(-2, 3):
                if mm + j > 0:
                    if (mm + j) ** 2 == m:
                        if mm + j > N:
                            ans -= 1
    print(ans)

    """
    # guchoku
    cnt = 0
    ok = [0] * (R - L + 1)
    for i in range(L, R+1):
        flg = 1
        for d in range(2, 101):
            if i % (d**2) == 0:
                flg = 0
                break
        cnt += flg
        if flg:
            ok[i - L] = 1
    print(cnt)
    """


if __name__ == '__main__':
    main()