160638

When I start, the first coordinate I choose is the center coordinate (6,6). Then, since I am in the middle of the sand block I can easily divide the block into four squares. After splitting the board, I choose one of the squares randomly and type in the coordinate that is the center of the chosen square. When it gives me the number of steps to get to the treasure I can figure out if the treasure is inside that square or not. If I have to, I can repeat the strategy for every square.
It took me three guesses to choose the correct coordinate.