Joust Sort

We are going to organise the letters of the word using a novel algorithm based
on the natural instincts of the hoarse chestnut tree: a grand tournament
between its constituent letters.

We will pick several pairs of letters and have them face off. The result of a match between these
letters determines their relative order. For example, if , then all occurrences of  in a well-organised
word should come before all occurrences of  in that word. If there is no case for  or , then
the individual letters  and  may intersperse among each other in any order.

Given a word, and several such matches, determine a fair rearrangement of the word to meet all of
the constraints given. It is possible that multiple such rearrangements exists, or that none exist at all.

Input
  itemize
    One line containing the number of orders to follow,  ().
     further lines, each containing a distinct ordering of two lowercase
          letters  and  separated by a < or > character and spaces.
    One final line containing the word to improve,  (.
  itemize

Output
  Output a sorted version of the word, or IMPOSSIBLE if the word cannot
  be sorted according to all of the rules at once.

  In case there are multiple answers, you may output any one of them.