#include <bits/stdc++.h>

using namespace std;

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