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

typedef long long ll;
#define PB push_back

int main() {
	ios_base::sync_with_stdio(false); cin.tie(0);
	int n; cin >> n;
	ll sum = 0;
	for (int i = 1; i <= n; ++i) {
		if (i % 3 != 0 && i % 5 != 0) sum += i;
	}
	cout << sum;
}
