
#include <iostream>



using namespace std;

int N;



int main()
{

	cin >> N;

	long long ans = 0;


	for (int i = 1; i <= N ; i++) {
		if (i % 3 && i % 5) {
			ans += (long long)i;
		}
	}

	cout << ans << endl;

	return 0;
}
