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

int main() {
	int N;
	cin >> N;

	ll ans = 0;
	rep(i, N) {
		if(i % 3 != 0 && i % 5 != 0)
			ans += i;
	}

	cout << ans << endl;

	return 0;
}