// -----------------------------------
// Author     : MatsuTaku
// Country    : Japan
// Created    : 04/12/20 20:48:37
// -----------------------------------

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

int main() {
  cin.tie(nullptr); ios::sync_with_stdio(false);

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

  return 0;
}
