Black-and-White Cube

0ms

262144K

Description:

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 k³ 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.

Input:

The first line contains integer k (1 ≤ k ≤ 100), which is size of the cube.

Output:

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.

Sample Input:

Sample Output:

-1

Sample Input:

Sample Output:

bb
ww

bb
ww

Informação

Provedor Codeforces

Código CF323A