. 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 3 4 5 6 7 2 . 2.5 1 - 2 1 - 2 1 - 2 1 - 2 2 - 3 0.5 2.5