Question 141
There is a $20 \times 20$ table and $400$ cards printed with the numbers $1$ to $400$. The cards are then distributed to the cells of the table so that there is one card in each cell. After that, we put a red sticker on the card with the largest number in each row, and a blue sticker on the card with the largest number in each column. Let $A$ denote the smallest number on the $20$ cards with red stickers, and $B$ denote the smallest number on the $20$ cards with blue stickers. How many different possible values of $|A - B|$ are there?