#include <bits/stdc++.h>
using namespace std;

int main() {
    int n;
    cin >> n;

    vector<int> cnt(n + 1, 0);


    for (int i = 2; i <= n; i++) {
        if (cnt[i] == 0) {
            for (int j = i; j <= n; j += i) {
                int x = j;
                while (x % i == 0) {
                    cnt[j]++;
                    x /= i;
                }
            }
        }
    }

    vector<bool> prime(n + 1, true);
    prime[0] = prime[1] = false;

    for (int i = 2; i * i <= n; i++) {
        if (prime[i]) {
            for (int j = i * i; j <= n; j += i) {
                prime[j] = false;
            }
        }
    }

    int ans = 0;

    for (int i = 2; i <= n; i++) {
        if (prime[cnt[i]]) {
            ans++;
        }
    }

    cout << ans;
}