Flowerbed Redecoration

Joon-Pyo decorated a flowerbed in front of his home. The flowerbed is in the shape of an $$$n \times m$$$ grid, and one flower is planted in each cell. There are 26 colors, one corresponding to each uppercase letter from A to Z. Suddenly, he wanted to redecorate the flowerbed.

1. Place the equipment so that exactly the flowers in the first $$$d$$$ rows and the first $$$d$$$ columns are inside.
2. Rotate the $$$d \times d$$$ square inside the equipment $$$90^\circ$$$ clockwise. If this square contains flowers from the last $$$d$$$ rows and the last $$$d$$$ columns, then the construction is finished. Otherwise, if this square does not contain flowers in the last $$$d$$$ columns, move the equipment $$$x$$$ squares to the right. Otherwise, move the equipment down by $$$y$$$ squares and all the way to the left so it contains flowers from the first $$$d$$$ columns.
3. Repeat step 2 until construction is finished.

Note that the equipment will never go out of the flowerbed, as $$$x$$$, $$$y$$$, and $$$d$$$ are carefully determined before construction begins.

He cannot start construction without knowing the outcome. Write a program that outputs the result.