#include <stdio.h>
#include <stdlib.h>

struct Zero {} ;

template <typename N>
struct Succ {} ;


template <typename N, typename M>
struct Add {} ;

/*
 Create new template specializations of Add here 
 so that this code compiles and works.
 */


template <typename N>
struct Eval {} ;

template <>
struct Eval<Zero> { 
  enum { value = 0 } ;
} ;

template <typename N>
struct Eval< Succ<N> > {
  enum { value = Eval<N>::value + 1 } ;
} ;



int main(int argc, char* argv[]) {

  /* This should print `2 + 3 = 5`: */
  printf("2 + 3 = %i\n", 
         Eval< Add< Succ<Succ<Zero> >,
                    Succ<Succ<Succ<Zero> > > > :: result > :: value ) ;  

  return EXIT_SUCCESS ;
}