from math import isqrt

import numpy as np

ceil_sq = lambda n: 1 + isqrt(n - 1)

L, R = map(int, input().split())
res = np.ones(R - L + 1, dtype=bool)


def primes_np(n):
    is_prime = np.ones(n + 1, dtype=bool)
    is_prime[0] = False
    is_prime[1] = False
    for i in range(2, int(n**0.5) + 1):
        if not is_prime[i]:
            continue
        is_prime[i * 2 : n + 1 : i] = False
    return np.where(is_prime)[0].tolist()


# 10^6以下の素数の2乗で割り切れるかどうかを調べる
for p in primes_np(10**6 + 1):
    p2 = p**2
    res[((L - 1) // p2) * p2 + p2 - L : R - L + 1 : p2] = False

# 10^6~10^9の素数の2乗で割り切れるかどうかを調べる
for i in range(1, 10**6 + 1):
    if L < i:
        break
    l_sqrt = ceil_sq(L // i)
    r_sqrt = isqrt(R // i)
    for n in range(l_sqrt, r_sqrt + 1):
        if n <= 1:
            continue
        if L <= i * n**2 <= R:
            res[i * n**2 -L] = False
print(res.sum())