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

int main() {
	int n; cin >> n;
	
	long long cnt = 0;
	for (int i = 1; i <= n; ++i) {
		if (i%3 != 0 && i%5 != 0) {
			cnt += i;
		}
	}
	
	cout << cnt << endl;
	
	return 0;
}
