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

void solve() {
    ll n, c = 0;
    cin >> n;
    for (ll x = 1; x <= n; x++) {
        for (ll a = 1; a * a <= x; a++) {
            if (x % a == 0) {
                ll b = x / a;
                if (abs(a - b) <= 1) {
                    c++;
                    break;
                }
            }
        }
    }
    cout << c << "\n";
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    solve();
    return 0;
}