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

int main() {

	int n;
	cin >> n;

	ll ans = 0ll;
	for(int i = 1; i <= n; i++) {
		if(i % 3 == 0 || i % 5 == 0) continue;
		else ans += (ll)i;
	}

	cout << ans << endl;

	return 0;
}
