import math, sys
L,R = map(int,input().split())
if R == 1:
    print(1)
    sys.exit()
# 素数リスト作成
def seachPrimeNum(N):
    max = int(N**0.5)
    seachList = [i for i in range(2,N+1)]
    primeNum = []
    while seachList[0] <= max:
        primeNum.append(seachList[0])
        tmp = seachList[0]
        seachList = [i for i in seachList if i % tmp != 0]
    primeNum.extend(seachList)
    return primeNum

PL = seachPrimeNum(math.ceil(pow(R,1/3)))
A = list(range(L,R+1))


for p in PL:
    p2 = p*p 
    for i in range(-(-L//p) * p - L, R//p * p - L + 1):
        j = 0
        while A[i] % p == 0:
            if j == 1:
                A[i] = -1
            else:
                A[i] //= p
            j += 1

def check(x,y):
    return x >= y*y
for i in range(R-L):
    a = A[i]
    if a > 1:
        lb = 0
        ub = R
        while ub - lb > 1:
            mid = (ub + lb) //2
            if check(a,mid):
                lb = mid
            else:
                ub = mid
        if a == lb * lb:
            AL[i] = -1
#print(A)
ans = 0
for a in A:
    if a > 0:
        ans += 1
print(ans)