The squares of a rectanglar board of 11 rows and 9 columns are numbered sequentically 1 through 99 with a hidden monetary reward between 0 and 20 dollars assigned to each square. A game using the board requires the player to choose a square by selecting any two-digit number and then subtracting the sum of its two digits from the selected number. The player then receives the reward assigned to the 99 squares to minimize the player's reward (regardless of how many times the game is repeated)? To make the game interesting, the assignment of $0 to all the squares is not an option.