import sys
from collections import defaultdict
sys.setrecursionlimit(10**7)
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LI2(): return list(map(int,sys.stdin.readline().rstrip()))
def S(): return sys.stdin.readline().rstrip()
def LS(): return list(sys.stdin.readline().rstrip().split())
def LS2(): return list(sys.stdin.readline().rstrip())


L,R = MI()

X = [i for i in range(L,R+1)]
for i in range(2,10**6+1):
    s = i**2
    for j in range(s*((L+s-1)//s)-L,s*(R//s+1)-L,s):
        X[j] = 0
    for j in range(i*((L+i-1)//i)-L,i*(R//i+1)-L,i):
        if X[j] % i == 0:
            X[j] //= i


def is_square(x):
    y = int(x**.5)
    for i in range(y-1,y+2):
        if i**2 == x:
            return True
    return False


ans = 0
for x in X:
    if x == 1:
        ans += 1
    elif x == 0:
        continue
    else:
        if not is_square(x):
            ans += 1

print(ans)