#include<iostream>
#include<string>

using namespace std;

typedef long long ll;

ll N;

int main() {
	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;
	return 0;
}