#include <bits/stdc++.h>  
using namespace std;  
typedef long long ll; 
typedef long double ld; 
const int INF = 0x3f3f3f3f;  
const int N = 200000 + 5;

int main()
{
	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 << endl;
    return 0;
}