// By Atul Rathore

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

#define ll long long int
#define f(n) for(int i=0;i<n;i++)
#define p(x) cout<<x<<endl;
#define fastio ios::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
	


int main()
{
	fastio;
	int n;
	cin>>n;
	ll sum=0;
	for(int i=1;i<=n;i++)
	{
		if(i%3!=0 && %5!=0)sum+=i;
	}
	cout<<sum<<endl;
	
	
	
}
