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

int main() {
  int n;
  unsigned long int sum = 0;
  cin >> n;

  for (int i = 1; i < n; ++i) {
    if (i % 3 != 0 && i % 5 != 0) {
      sum += i;
    }
  }

  cout << sum << endl;
}
