Chess board (4) X42055

Write code for, given a non-negative integer $n$, where $n=2^k$ for some $k \geq 1$, printing a chess board of size $n$, as shown in the examples.

The program must implement and use the CHESS-BOARD function, which can be iterative or recursive and is not allowed to perform input/output operations.

Make one submission with Python code and another submission with C++ code.

Input

The input is an integer $n$ of the form $n=2^k$ for some $k \geq 1$.

Output

The output is a chess board of size $n$.

Observation

The size $n$ of a chess board is always of the form $n=2^k$ for some $k \geq 1$.