#include <bits/stdc++.h>
#define ll long long
using namespace std;

int main()
{
	int n;
	scanf("%d",&n);
	ll ans = 0;
	for(int i = 1 ; i <= n ; i++)
	{
		if (i%3 != 0 && i%5 != 0) ans += i;
	}
	printf("%lld\n",ans);
	return 0;
}
