#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using P = pair<int, int>;
// Welcome to my source code!

int main() {
    int n;
    cin >> n;
    ll ans = 0;
    for (int i = 1; i <= n; i++) {
        if (i % 3 == 0 || i % 5 == 0) continue;
        ans += i;
    }
    cout << ans << endl;
}