import sys
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

primes = sieve(10**6)

def is_prime(n):
    if n < 2:
        return False
    for p in [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37]:
        if n % p == 0:
            return n == p
    d = n - 1
    s = 0
    while d % 2 == 0:
        d //= 2
        s += 1
    for a in [2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37]:
        if a >= n:
            continue
        x = pow(a, d, n)
        if x == 1 or x == n - 1:
            continue
        for _ in range(s - 1):
            x = pow(x, 2, n)
            if x == n - 1:
                break
        else:
            return False
    return True

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

    # Mark multiples of squares of primes up to 1e6
    for p in primes:
        p_sq = p * p
        if p_sq > R:
            continue
        start = ((L + p_sq - 1) // p_sq) * p_sq
        for m in range(start, R + 1, p_sq):
            idx = m - L
            if 0 <= idx < size:
                is_square_free[idx] = False

    # Check for squares of primes larger than 1e6
    for i in range(size):
        if not is_square_free[i]:
            continue
        x = L + i
        sqrt_x = math.isqrt(x)
        if sqrt_x * sqrt_x == x and is_prime(sqrt_x):
            is_square_free[i] = False

    return sum(is_square_free)

L, R = map(int, sys.stdin.readline().split())
print(count_square_free(L, R))