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

int main() {
  int N;
  cin >> N;
  int64_t sum = 0;
  for (int i = 1; i <= N; i++) {
    if (i%3 != 0 && i%5 != 0) sum += i;
  }
  cout << sum << endl;
}
