E. Chessboardtime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputChessboard is a board of n × n squares arranged in two alternating colors (black and white). Top left square is white. You are given board size n. Output an image of a chessboard, with black and white squares marked with '#' and '.' characters, respectively.InputThe only line of input contains an integer n (1 ≤ n ≤ 9).OutputOutput an image of n × n chessboard.ExamplesInput4Output.#.##.#..#.##.#.
Input4
Output.#.##.#..#.##.#.
['*special problem', '*1900']