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