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

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