#include "bits/stdc++.h"
using namespace std;
typedef long long ll;
int main(int argc, char* argv[]) {
	ll n, answer = 0;
	cin >> n;
	for (int i = 1; i <= n; i++)
	{
		if (i % 3 != 0 && i % 5 != 0)
		{
			answer += i;
		}
	}
	cout << answer << endl;
	return 0;
}