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

int main(int argc, char const *argv[])
{
	int n;
	cin>>n;
	long long ans=0;
	for (int i = 1; i <= n; ++i)
	{
		if (i%3==0||i%5==0)
		{
			continue;
		}
		ans+=i;
	}
	cout<<ans<<endl;
	return 0;
}
