Tournament P26606

Consider an all-play-all tournament, in which each team (or player) will meet every other participant exactly once, in turns. For instance, if we have $n = 2m$ football teams, we will have $m$ concurrent matches in $n - 1$ different days. In the end, we aim for each team to have competed against all the other teams. Additionally, for fairness, we want every team to play $m$ times at home and $m-1$ times away, or $m-1$ times at home and $m$ times away. A similar situation would arise in a chess tournament, where we require all the players to have as many white pieces as black pieces (plus minus one).

Given the $n$ names of the teams (or players), can you schedule all the matches?

Input

Input consists of several cases, each with $n$, followed by $n$ different names made up of only lowercase letters. Assume $2 \le n \le 1000$, and that $n$ is even.

Output

Print $n$ lines for each case. The first $n-1$ lines should have $m$ matches separated by spaces. A match is a pair of names separated by a dash, where the first team plays at home and the second team plays away. End each case with a line with 10 asterisks. Since there is more than one solution, print any one. Follow strictly the format of the sample output.