B'Little C loves number xc2 xab3 xc2 xbb very much. He loves all things about it. Now he is playing a game on a chessboard of size n x m . The cell in the x -th row and in the y -th column is called (x,y) . Initially, The chessboard is empty. Each time, he places two chessmen on two different empty cells, the Manhattan distance between which is exactly 3 . The Manhattan distance between two cells (x_i,y_i) and (x_j,y_j) is defined as |x_i-x_j|+|y_i-y_j| . He want to place as many chessmen as possible on the chessboard. Please help him find the maximum number of chessmen he can place. A single line contains two integers n and m ( 1 <= q n,m <= q 10^9 ) -- the number of rows and the number of columns of the chessboard. Print one integer -- the maximum number of chessmen Little C can place. In the first example, the Manhattan distance between any two cells is smaller than 3 , so the answer is 0 . In the second example, a possible solution is (1,1)(3,2) , (1,2)(3,3) , (2,1)(1,3) , (3,1)(2,3) . '...