#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < n; i++)
using namespace std;
using ll = long long;
int INF = 1000000009;
int main()
{
  int n;
  cin >> n;
  ll ans = 0;
  for (int i = 1; i <= n; i++)
  {
    if(!(i%5==0||i%3==0)){
      ans += i;
    }
  }
  cout << ans << endl;
}