On a 8 by 8 chessboard, 2 rooks are randomly placed on 2 different squares of the chessboard. The probability that these 2 rooks will be able to attack each other has the form \( \frac {a} {b} \), where \( a\) and \(b \) are coprime. What is \( a + b\)?
Note: Rooks can attack anywhere along the row and column they are in.