#include <bits/stdc++.h>

using namespace std;

int main() {
  int N;
  cin >> N;
  long long ans = 0;
  for (int i = 1; i <= N; i++) {
    if (i % 3 == 0 or i % 5 == 0) continue;
    ans += i;
  }
  cout << ans << endl;

  return 0;
}
/* vim:set fdm=marker: */
