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