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