#include <stdio.h>
class element
{
public:
int value;
element *left,*right,*daddy;
element()
{
left=0;
right=0;
daddy=0;
value=0;
}
};
class tree
{
public:
 element *min,*root;
 int noe;
 void put(element *w, element *b)
 {
  if(w->value>b->value)
  {
   if(b->right!=0)
    put(w,b->right);
   else
   {
    b->right=w;
    w->daddy=b;
   }
  }
  else
  {
   if(b->left!=0)
    put(w,b->left);
   else
   {
    b->left=w;
    w->daddy=b;
    if(min->value>=w->value)
     min=w;
   }
  }
 }
 void findMin(element *subtree)
 {
  element *horse;
  horse=subtree;
  while(horse->left)
   horse=horse->left;
 min=horse;
 }
 tree()
 {
  root=0;
  noe=0;
  min=0;
 }
 void add(int in)
 {
  element *add;
  add=new element;
  add->value=in;
  if(root)
  {
   put(add,root);
  }
  else
  {
   root=add;
   min=add;
  }
  noe++;
 }
 void removeMin()
 {
  if(noe==1)
  {
   root=0;
   min=0;
  }
  else
  {
   if(root==min)
   {
    root=root->right;
    findMin(root);
   }
   else
   {
    if(min->right)
    {
     min->daddy->left=min->right;
     min->right->daddy=min->daddy;
     findMin(min->right);
    }
    else
    {
     min->daddy->left=0;
     min=min->daddy;
    }
   }
  }
  noe--;
 }
};
void solution(int n)
{
tree t;
int in;
for(int i=0;i<n;i++)
{
scanf("%d",&in);
t.add(in);
}
tree ta;
tree tb;
int i=0;
while(t.noe)
{
  if(!(i%2))
  {
  ta.add(t.min->value);
  t.removeMin();
  tb.add(t.min->value);
  t.removeMin();
  }
  else
  {
   tb.add(t.min->value);
   t.removeMin();
   ta.add(t.min->value);
   t.removeMin();
  }
  i++;
}

while(ta.noe)
{
    printf("%d-A ",ta.min->value);
    ta.removeMin();
    if(tb.noe)
    {
     printf("%d-B ",tb.min->value);
     tb.removeMin();
    }

}
printf("\n");
}
int main()
{
int n=1;
while(n)
{
scanf("%d",&n);
solution(n);
}
return 0;
}