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

int main() {

    int n;
    cin >> n;
    ll sum = 0;
    for (ll i = 1; i <= n; i++) {
        if (i % 3 != 0 && i % 5 != 0) {
            sum += i;
        }
    }
    cout << sum << endl;

    return 0;

}
