#include <iostream>
#include <algorithm>
#include <vector>
#include <string>

#define endl '\n'
#define ll long long

using namespace std;

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int n;
	cin >> n;

	long long sum = 0;
	for (int i = 1; i <= n; i++)
	{
		if (i % 3 == 0 || i % 5 == 0) continue;
		sum += i;
	}
	cout << sum << endl;

	return 0;
}