#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;
}

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