Texture Tile

A square raster image is represented by an $N \times N$ array of pixels. A texture tile is a square (sub)image whose first row is identical to its last row and whose first column is identical to its last column. This property is useful when covering the surface of a graphics object with repeated copies of a texture, because it lets adjacent copies join together "seamlessly".

Given an image, find the side length of the largest square subimage that is a texture tile.

The first token is the integer $N$. It is followed by $N^2$ integers $c_{i,j}$, the pixel values, given row by row (row $1$ first, then row $2$, and so on).

Print a single integer $m$: the side length of the largest texture tile contained in the image. (Since a single pixel is always a texture tile, $m \ge 1$ always holds.)

• $1 \le N \le 370$
• $0 \le c_{i,j} \le 255$