48
x 1 x 2 x 1 x -1 t 1 x -1 x -1 x 1 t 1 t -1 x 1 t 2 x 1 x 2 t 1 x 1 x -1 x -2 x 1 x 1 t 1 x 1 t 1 x 1 x 1 x 1 t 1 x 1 x 1 x 1 x 1 x 1 x 1 x -1 t 1 x 1 x -1 x -1 t 1 x 1 t 1 x 1 x 1 x -1 t 1 t -1 t -1 x 1