#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;
signed main() {
  ios::sync_with_stdio(false); cin.tie(0);
  int n;
  cin >> n;
  long long ans = 0;
  for (int i = 1; i <= n; i++) {
    if (i % 3 != 0 && i % 5 != 0) ans += i;
  }
  cout << ans << endl;
  return 0;
}