6 pairs of model 1, 6 pairs of model 19, 6 pairs of model 2, 6 pairs of model 10, 6 pairs of model 11, 6 pairs of model 18, 6 pairs of model 6, 6 pairs of model 5, 6 pairs of model 9, 6 pairs of model 20, 6 pairs of model 12, 6 pairs of model 17, 6 pairs of model 7, 6 pairs of model 4, 6 pairs of model 21, 6 pairs of model 22, 6 pairs of model 13, 6 pairs of model 16, 6 pairs of model 8, 6 pairs of model 23, 6 pairs of model 3, 6 pairs of model 24, 6 pairs of model 14, 6 pairs of model 15