Weird I know, but if you do the practice inputs with this, they won't work if you translate directly from 5 5 to mean 5 rows and 5 columns.  What it means in this case I think is that the grid goes from 0,0 to 5,5.  So the height and width of this grid is actually 6x6.  Believe me I thought it was weird too but the example inputs don't work without the +1.  :frowning: