#include <iostream>
#include <vector>
using namespace std;

int main()
{
  int count, tmp;
  vector<int> packs;
  
  while(1)
  {
    cin >> count;
    
    if(count == 0) break;
    
    packs.clear();
    for(int i = 0; i < count; ++i)
    {
      cin >> tmp;
      packs.push_back(tmp);
    }
    sort(packs.begin(), packs.end());
    
    bool je = true;
    int i = 0, j = packs.size() - 1;
    for(; i < j; ++i, --j)
    {
      if(je)
      {
        if(i > 0) cout << " ";
      cout << packs[i] << "-A";
      cout << " " << packs[j] << "-B";
      }
      else
      {
        cout << " " << packs[j] << "-A";
        cout << " " << packs[i] << "-B";
      }
      je = !je;
    }
    if(i == j)
    {
      if(je)
      {
        if(i > 0) cout << " ";
        cout << packs[i] << "-A";
      }
      else
      {
        cout << " " << packs[j] << "-A";
      }
    }
    cout << endl;
  }
  
  return 0;
}