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

int main() {
  ll n,ans = 0;
  cin >> n;
  for(int i = 1;i < n;i++){
    if(i%3 != 0 && i%5 != 0) ans += i;
  }
  cout << ans << endl;
}
