Consider the game tic-tac-toe. let's define x n as the number of rows, columns, or diagonals with exactly n x's and no o's. similarly o n is the number of rows, columns, or diagonals with just n o's. the utility function assigns +1 to any position with x 3 = 1 and -1 to any position with o 3 = 1 . all other terminal positions have utility 0. for nonterminal positions, we use the following heuristic: h(s) = 3x2(s) + x1(s) − (3o2(s) + o1( approximately, how many possible games of tic tac toe are there?