Your task is to fill an $n \times m$ grid using L-trominos (three squares that have an L-shape). For example, here is one way to fill a $4 \times 6$ grid:
The first input line has an integer $t$ : the number of tests.
After that, there are $t$ lines that describe the tests. Each line has two integers $n$ and $m$ .
For each test, print YES if there is a solution, and NO otherwise.
If there is a solution, also print $n$ lines that each contain $m$ letters between A–Z. Adjacent squares must have the same letter exactly when they belong to the same tromino. You can print any valid solution.
2 4 6 4 7
\n · \n · \n
YES AADDBB ACCDEB BCAEEC BBAACC NO
\n \n \n \n \n \n