B'Drazil created a following problem about putting 1 xe2 x80 x89 xc3 x97 xe2 x80 x892 tiles into an n xe2 x80 x89 xc3 x97 xe2 x80 x89m grid: "There is a grid with some cells that are empty and some cells that are occupied. You should use 1 xe2 x80 x89 xc3 x97 xe2 x80 x892 tiles to cover all empty cells and no two tiles should cover each other. And you should print a solution about how to do it." But Drazil doesn 't like to write special checking program for this task. His friend, Varda advised him: "how about asking contestant only to print the solution when it exists and it is unique? Otherwise contestant may print 'Not unique ' ". Drazil found that the constraints for this task may be much larger than for the original task! Can you solve this new problem? Note that you should print 'Not unique ' either when there exists no solution or when there exists several different solutions for the original task. The first line contains two integers n and m (1 xe2 x80 x89 xe2 x89 xa4 xe2 x80 x89n, xe2 x80 x89m xe2 x80 x89 xe2 x89 xa4 xe2 x80 x892000). The following n lines describe the grid rows. Character '. ' denotes an empty cell, and the character '* ' denotes a cell that is occupied. If there is no solution or the solution is not unique, you should print the string "Not unique". Otherwise you should print how to cover all empty cells with 1 xe2 x80 x89 xc3 x97 xe2 x80 x892 tiles. Use characters "<>" to denote horizontal tiles and characters "^v" to denote vertical tiles. Refer to the sample test for the output format example. In the first case, there are indeed two solutions: and so the answer is "Not unique".'...