import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
sys.setrecursionlimit(10**7)
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################



import math

def pi(n):
    if n<=1:
        return 0
    m = int(math.sqrt(n))
    keys = [n // i for i in range(1, m + 1)]
    keys += range(keys[-1] - 1, 0, -1)
    h = {i : i - 1 for i in keys}
    for i in range(2, m + 1):
        if h[i] > h[i - 1]:
            hp = h[i - 1]
            i2 = i * i
            for j in keys:
                if j < i2: break
                h[j] -= h[j // i] - hp

    return h[n]

L,R = na()
print(pi(R)-pi(L-1)+pi(2*R-1)-pi(2*L))