## https://yukicoder.me/problems/no/1653

import math

def main():
    L, R = map(int, input().split())

    # 10 ** 6 以下の素数をまず列挙
    target_max = 10 ** 6
    primes = []
    is_prime = [True] * (target_max + 1)
    for p in range(2, target_max + 1):
        if not is_prime[p]:
            continue

        x = 2 * p
        primes.append(p)
        while x <= target_max:
            is_prime[x] = False
            x += p
        
    target_divisors = {}
    for l in range(L, R + 1):
        target_divisors[l] = []

    for p in primes:
        q = R // p
        v = q * p
        while v >= L:
            if v in target_divisors:
                target_divisors[v].append(p)
                if v % (p ** 2) == 0:
                    del target_divisors[v]

            v -= p
    
    # 残ったtarget_divisorたちから10**6以下の数字を割っていく
    answer = 0
    for v, single_divisors in target_divisors.items():
        for d in single_divisors:
            v //= d

        if v == 1:
            answer += 1
            continue

        low = 0
        high = 10 ** 9
        while high - low > 1:
            mid = (high + low) // 2
            if mid ** 2 <= v:
                low = mid
            else:
                high = mid
        if high ** 2 <= v:
            w = high
        else:
            w = low

        if w ** 2 < v:
            answer += 1
    print(answer)





    



if __name__ == "__main__":
    main()