Grammy is a puzzle master. Today, she is playing a variant of "Star Battle" puzzle.
The puzzle consists of a
(4n)×(4n)(4n) \times (4n)(4n)×(4n) grid. The grid is divided into
4n4n4n blocks, but each block may be disconnected. The goal is to place stars into the grid so that each row, each column, and each block contains exactly
nnn stars. Additionally, two stars cannot be adjacent, diagonally or orthogonally. In other words, two stars cannot be placed in two cells that share an edge or a corner.
The left picture illustrates a
4×44\times 44×4 empty puzzle, and the right picture shows a solution to the puzzle.
Grammy surely knows how to solve the puzzle, but she decided to give you a quiz. Please solve the puzzle.