#include <iostream>
using namespace std;
using ll = long long;

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