#include<bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; i++)
using namespace std;
using ll = long long;

int main()
{
  int N;
  cin >> N;
  
  ll sum = 0;
  rep(i, N)
  {
    if ((0 != i % 3) && (0 != i % 5))
    {
      sum += i;
    }
  }
  
  cout << sum << endl;

  return 0;
}