import math
import sys

input = sys.stdin.readline

min, max = map(int, input().split())

arr = [False] * (max - min + 1)

for i in range(2, int(math.sqrt(max))+1):
    pow = i * i
    start_index = int(min/pow)
    if min % pow != 0:
        start_index+=1
    for j in range(start_index, int(max/pow)+1):
        arr[int(j*pow-min)]=True

count = 0

for i in range(0, max-min+1):
    if not arr[i]:
        count += 1

print(count)