l = int(input())
g = 0
for num in range(1,l+1):
    a = []
    i = 2
    n = num
    while i * i <= n:
        while n % i == 0:
            a.append(i)
            n //= i
        i += 1
    if n > 1:
        a.append(n)
    if len(set(a)) == 2:
        g += 1
print(g)