import math

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

def count_square_free(L, R):
    primes = sieve(10**6)
    size = R - L + 1
    is_square_free = [True] * size

    for p in primes:
        s = p * p
        if s > R:
            continue
        start = ((L + s - 1) // s) * s
        if start > R:
            continue
        for k in range(start, R + 1, s):
            idx = k - L
            is_square_free[idx] = False

    for i in range(size):
        if is_square_free[i]:
            x = L + i
            root = math.isqrt(x)
            if root * root == x:
                if root > 1:
                    is_square_free[i] = False

    return sum(is_square_free)

L, R = map(int, input().split())
print(count_square_free(L, R))