import math

def sieve(n):
    sieve = [True] * (n + 1)
    sieve[0] = sieve[1] = False
    for i in range(2, int(math.isqrt(n)) + 1):
        if sieve[i]:
            sieve[i*i : n+1 : i] = [False] * len(sieve[i*i : n+1 : i])
    primes = [i for i, is_p in enumerate(sieve) if is_p]
    return primes

def is_prime(n):
    if n <= 1:
        return False
    if n <= 3:
        return True
    if n % 2 == 0 or n % 3 == 0:
        return False
    i = 5
    w = 2
    while i * i <= n:
        if n % i == 0:
            return False
        i += w
        w = 6 - w
    return True

def count_squarefree(L, R):
    primes = sieve(10**6)
    count = 0
    for x in range(L, R + 1):
        if x == 0:
            continue
        if x == 1:
            count += 1
            continue
        square_free = True
        for p in primes:
            p_sq = p * p
            if p_sq > x:
                break
            if x % p_sq == 0:
                square_free = False
                break
        if not square_free:
            continue
        s = math.isqrt(x)
        if s * s != x:
            count += 1
        else:
            if s == 1:
                count += 1
            else:
                if not is_prime(s):
                    pass
                else:
                    pass
    return count

# Read input
L, R = map(int, input().split())
print(count_squarefree(L, R))