The cows have taken up the game of checkers with a vengeance.
Unfortunately, despite their infinite enjoyment of playing, they are terrible at the endgame. They want your help.
Given an NxN (4 <= N <= 30) checkboard, determine the optimal set of moves to end the game on the next move. Checkers move only on the '+' squares and capture by jumping 'over' an opponent's piece.
The piece is removed as soon as it is jumped. See the example below where N=8:

- + - + - + - + The K's mark Bessie's kings; the o's represent the + - + - + - + - opponent's checkers. Bessie always moves next. The - + - K - + - + Kings jump opponent's checkers successively in any + - + - + - + - diagonal direction (and removes pieces when jumped). - o - o - + - + + - K - + - + - For this board, the solution requires the lower left - o - + - + - + King to jump successively across all three of the + - K - + - K - opponents' checkers, thus ending the game (moving K marked as >K<): Original After move 1 After move 2 After move 3 - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - - + - K - + - + - + - K - + - + - + - K - + - + - + - K - + - + + - + - + - + - + - + - + - + - + ->K<- + - + - + - + - + - + - - o - o - + - + - o - o - + - + - + - o - + - + - + - + - + - + + - K - + - + - >K<- K - + - + - + - K - + - + - + - K ->K<- + - - o - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + + ->K<- + - K - + - + - + - K - + - + - + - K - + - + - + - K - The moves traversed these squares: 1 2 3 4 5 6 7 8 R C 1 - + - + - + - + start: 8 3 2 + - + - + - + - move: 6 1 3 - + - K - + - + move: 4 3 4 + - * - + - + - move: 6 5 5 - o - o - + - + 6 * - K - * - + - 7 - o - + - + - + 8 + - K - + - K -Write a program to determine the (unique, as it turns out) game-ending sequence for an NxN input board if it exists. There is at least a king and at least one opponent piece on the board.

* Line 1: A single integer: N
* Lines 2..N+1: Line i+1 contains N characters (each one of: '-', '+', 'K', or 'o') that represent row i of a proper

* Lines 1..?: If this sequence of moves is impossible, output "impossible" on a line by itself. If such a sequence exist, each line contains two space-separated integers that represent successive locations of a king whose moves will win the game.