import sys

# sys.setrecursionlimit(200005)
int1 = lambda x: int(x)-1
pDB = lambda *x: print(*x, end="\n", file=sys.stderr)
p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr)
def II(): return int(sys.stdin.readline())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]
def LI1(): return list(map(int1, sys.stdin.readline().split()))
def LLI1(rows_number): return [LI1() for _ in range(rows_number)]
def SI(): return sys.stdin.readline().rstrip()

# dij = [(0, 1), (-1, 0), (0, -1), (1, 0)]
dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)]
inf = (1 << 63)-1
# inf = (1 << 31)-1
# md = 10**9+7
md = 998244353

mx = 1000001
sq = set()
for a in range(2, mx): sq.add(a**2)

l, r = LI()
r += 1
# a^2*b
dp = [0]*(r-l)

for a in sq:
    if a > r: continue
    s = (l+a-1)//a*a
    for i in range(s, r, a):
        dp[i-l] = 1

for a in range(1, mx):
    s = (l+a-1)//a*a
    for i in range(s, r, a):
        if i//a in sq: dp[i-l] = 1

print(r-l-sum(dp))