#include <bits/stdc++.h>
using namespace std;
 
int main() {
  long long N, ans = 0;
  cin >> N;
  for (int i=1; i<=N; i++){
    if(i%3 == 0 && i%5 == 0)
      continue;
    else if(i%3 == 0 || i%5 == 0)
      continue;
    else
      ans += i;
  }
  cout << ans << endl;
}