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