#include <bits/stdc++.h>
using ll = long long int;
using namespace std;
ll mod=1e9+7;
      
      
int main(){
  ll ans=0;
  int n;
  cin >> n;
  for(int i=1;i<=n;i++){
    if(i%3!=0 && i%5!=0){ans+=i;}
  }
  cout << ans << endl;
}