import numpy as np


def primes_np(n):
    is_prime = np.ones(n + 1, dtype=bool)
    is_prime[0] = False
    is_prime[1] = False
    for i in range(2, int(n ** 0.5) + 1):
        if not is_prime[i]:
            continue
        is_prime[i * 2:n + 1:i] = False
    return np.where(is_prime)[0]


N = int(input())
table = np.arange(N + 1, dtype=int)
for p in primes_np(N):
    p2 = p ** 2
    pp = p2
    while pp <= N:
        table[pp::pp] //= p2
        pp *= p2
ans = np.floor((N // table[1:]) ** .5).astype(int).sum()
print(ans)