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

int main() {
  int n;
  cin >> n;

  long long sum = 0;
  
  for (int i = 1; i <= n; i++) {
    if (i % 3 == 0 || i % 5 == 0) continue;
    sum += i;
  }

  cout << sum << endl;

  return 0;
}
