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

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