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