# include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 100; 
int main(){
	ios::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);
	int n;
	long long sum = 0;
	cin >> n; 
	for(int i = 1; i <= n; i++){
		if(i % 3 == 0 || i % 5 == 0)continue;
		sum += i;
	}
	cout << sum << '\n';
}