#include <iostream>

using namespace std;

int main() {

	long long N;
	cin >> N;

	long long sum = 0;
	for (long long i = 1; i <= N; ++i)
	{
		if ((i % 3 == 0) || (i % 5 == 0)) {
			
		}
		else {
			sum += i;
		}
	}

	cout << sum << endl;

	return 0;
}