import sys
input = lambda : sys.stdin.readline().rstrip()

sys.setrecursionlimit(2*10**5+10)
write = lambda x: sys.stdout.write(x+"\n")
debug = lambda x: sys.stderr.write(x+"\n")
writef = lambda x: print("{:.12f}".format(x))

def isqrt(n):
    """x*x<=nなる最大のx
    """
    x,y = n, (n+1)//2
    while y<x:
        x,y = y, (y + n//y) // 2
    return x

l,r = list(map(int, input().split()))
ok = [1]*(r-l+1)
# ok[i] : l+i
for i in range(2, 1010):
    ii = i*i
    ll = ((l+ii-1)//ii)*ii
    for k in range(ll, r+1, ii):
        ok[k-l] = 0
for i in range(1,r-l+1):
    ir = r//i
    k = isqrt(ir)
    kk = k*k
    if k>1 and l<=i*kk<=r:
        while i*kk-l>=0:
            ok[i*kk-l] = 0
            i -= 1
ans = sum(ok)
print(ans)