#include<bits/stdc++.h>
using namespace std;
#define mem(a) memset(a,0,sizeof(a))
#define ll long long
int main()
{
	int n,i;
	ll s=0;
	cin>>n;
	for(i=1;i<=n;i++)
	{
		if(i%3!=0&&i%5!=0)
			s+=i;
	}
	cout<<s;
	return 0;
}