18156번 - Black and White 다국어

문제

You are given an n-by-n grid where each square is colored either black or white. A grid is correct if all of the following conditions are satisfied:

• Every row has the same number of black squares as it has white squares.
• Every column has the same number of black squares as it has white squares.
• No row or column has 3 or more consecutive squares of the same color.

Given a grid, determine whether it is correct.

입력

The first line contains an integer n (2 ≤ n ≤ 24; n is even). Each of the next n lines contains a string of length n consisting solely of the characters ‘B’ and ‘W’, representing the colors of the grid squares.

출력

If the grid is correct, print the number 1 on a single line. Otherwise, print the number 0 on a single line.

제한

힌트