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

int main() {
  int n;
  int64_t ans = 0;
  cin >> n;
  for (int i = 0; i < n; i++) {
    if (i%3 != 0 && i%5 != 0) {
      ans += i;
    }
  }
  cout << ans << endl;
}