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