#include <bits/stdc++.h>
#define rep(i,n) for(int i = 0; i < n; i++)
using namespace std;
typedef long long ll;
typedef pair<int,int> P;

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;
}