5
(9, 7, 9) + lambda (31, 38, 1) = (8, 9, 2) - lambda (10, 5, 16)
(4, 7, 2) + lambda (1, 8, 18) = (8, 3, 2) + lambda (12, 6, 0)
(1, 1, 1) + lambda (-6, 15, -10) = (0, 0, 0) + lambda (0, 21, -4)
(1, 2, 3) + lambda (1, 2, 3) = (1, 2, 3) + lambda (1, 2, 3)
(0, 1, 0) + lambda (0, 1, 0) = (-1, 0, 0) + lambda (1, 0, 0)