In a $8 \times 8$ chessboard, a red knight and a blue knight are sitting at the corners. These two knights are each other's biggest enemy. Though they can move like an ordinary knight in chess (Moving two squares straight and then turning either right or left square), but now they are extremely furious to attack each other. So the red knight will only move either up or right direction from its previous position and likewise, the blue knight will only move either down or left direction from its previous position. Find out the probability that a knight can attack another knight.