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

#define ll long long

int main()
{
	int n;
	cin>>n;

	ll s=0;
	for(int i=0;i<=n;i++)
	{
		if(i%3==0||i%5==0)
		{

		}
		else
		{
			s+=i;
		}
	}
	cout<<s<<endl;
}
