楔数（くさびすう）

def prime_factorize(n):

    a = []

    while n % 2 == 0:

        a.append(2)

        n //= 2

    f = 3

    while f * f <= n:

        if n % f == 0:

            a.append(f)

            n //= f

        else:

            f += 2

    if n != 1:

        a.append(n)

    return a

​

N = int(input())

ans = 0

for i in range(1,N+1):

    p = prime_factorize(i)

    if len(p)==len(list(set(p))) and len(p)==3:

        ans+=1

​

print(ans)