#include <iostream>
#include <type_traits>


template <int SZ>
class Internal 
{
    char arr[SZ];
};

template < int SZ>
 struct  helper 
 {
 typedef typename std::enable_if<(SZ > 1000 && SZ <9999) ,Internal<SZ>>::type type;
 };
 
 template < int SZ>
 struct A : public  helper<SZ>::type
 {};

int main() {
  A<1024> x;
  
  //NG
  //A<-34> y;
  return 0;
}