#include <bits/stdc++.h>
#define rep(i, n) for(int i = 1; i <= (n); i++)
using namespace std;

signed main(void)
{
	int n;
	long long ans;
	cin >> n;
	ans = 0;
	rep(i, n)
	{
		if (i % 3 != 0 && i % 5 != 0)
			ans += i;
	}
	cout << ans << endl;
	return 0;
}
