#include<bits/stdc++.h> 
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp> 
#define mod 1000000007
#define mod2 998244353
#define int long long
#define endl "\n"
#define p_b push_back
#define m_p make_pair
#define fastIO ios_base::sync_with_stdio(false),cin.tie(NULL)
using namespace std;
using namespace __gnu_pbds;
template <class T> 
using _ost = tree<
		T, 
		null_type, 
		less<T>, 
		rb_tree_tag, 
        tree_order_statistics_node_update>;


int32_t main(){
 	fastIO;
	int n;cin>>n;
	int sm=0;
	for(int i=1;i<=n;i++){
		if(i%3==0||i%5==0);
		else{
			sm+=i;
		}
	}
	cout<<sm<<endl;
}