l,r=map(int,input().split())
x=[i for i in range(l,r+1)]
y=[2]
z=[0]*10**6
for i in range(3,10**6,2):
    if z[i]:
        continue
    y.append(i)
    for j in range(i,10**6,i):
        z[j]=1
for i in y:
    c=(i-l%i)%i
    for j in range(c,len(x),i):
        d=0
        while x[j] and x[j]%i==0:
            x[j]//=i;d+=1
        if d>=2:
            x[j]=0
ans=0
for i in x:
    if not i:
        continue
    q,w=2,10**9
    while w-q>1:
        m=(q+w)//2
        if m**2<=i:
            q=m
        else:
            w=m
    if q**2!=i:
        ans+=1
print(ans)