You are given a cube of size k × k × k , which consists of unit cubes. Two unit cubes are considered neighbouring, if they have common face. Your task is to paint each of k 3 unit cubes one of two colours (black or white), so that the following conditions must be satisfied: each white cube has exactly 2 neighbouring cubes of white color; each black cube has exactly 2 neighbouring cubes of black color.
输入描述:
The first line contains integer k(1 ≤ k ≤ 100), which is size of the cube.
输出描述:
Print -1 if there is no solution. Otherwise, print the required painting of the cube consequently by layers. Print a k × k matrix in the first k lines, showing how the first layer of the cube should be painted. In the following k lines print a k × k matrix — the way the second layer should be painted. And so on to the last k-th layer. Note that orientation of the cube in the space does not matter.Mark a white unit cube with symbol "w" and a black one with "b". Use the format of output data, given in the test samples. You may print extra empty lines, they will be ignored.
示例1
输出
-1<br />bb<br />ww<br /><br />bb<br />ww<br />
加载中...