#include <bits/stdc++.h>
using namespace std;
 
int main() 
{
	int N;
	cin >> N;
	
	long sum = 0;
	
	for(int i = 1; i <= N; i++){
		if(i % 3 == 0 || i % 5 == 0) continue;
		sum += i;
	}

	cout << sum << endl;
	
	return 0;
}