#include "bits/stdc++.h"
using namespace std;


int main()
{
	int64_t n;
	cin >> n;

	int64_t ans = 0;
	for (int64_t i = 1; i <= n; i++) {
		if (i % 3 != 0 && i % 5 != 0) {
			ans += i;
		}
	}

	cout << ans << endl;
}

