#include <iostream>
#include <string>

using namespace std ;


int main()
{
   int* ptr1 ;
   int* ptr2 ;
   ptr1 = new int ;
   *ptr1 = 11 ;

   ptr2 = ptr1 ;
   delete ptr2 ;
   //not valid
   cout << *ptr1 << endl ;

   cout << "-----------" << endl ;

   int* ptr3 ;
   int* ptr4 ;
   ptr3 = new int ;
   *ptr3 = 12 ;

   ptr4 = ptr3 ;
   delete ptr3 ;
   delete ptr4 ;
   cout << *ptr3 << endl ;


}