l,r=map(int,input().split())
dic=dict()
for i in range(l,r+1):
    dic[i]=1

for p in range(2,10**6+5):
    k=(l+p**2-1)//(p**2)
    while k*(p**2)<=r:
        dic[k*(p**2)]=0
        k+=1

for k in range(1,10**6+5):
    p=int((l//k)**0.5)
    while k*(p**2)<l:p+=1
    if p==1:p+=1
    while k*(p**2)<=r:
        dic[k*(p**2)]=0
        p+=1

ans=0
for i in range(l,r+1):
    ans+=dic[i]
print(ans)