#include <bits/stdc++.h>
using namespace std;
using ll = long long;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);

  ll N; cin >> N;
  ll ans = 0;
  for (ll i = 1; i <= N; i++) {
    if (i % 3 != 0 && i % 5 != 0) ans += i;
  }
  cout << ans << '\n';
  return 0;
}