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