#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;
#define F first
#define S second

int32_t main(){
	int n;
	cin >> n;
	ll sum = 0;
	for (int i = 1; i <= n; i++){
		if (i % 3 == 0 || i % 5 == 0);else{
			sum += i;
		}
	}
	cout << sum;
}
