2-3', 3-4', 4-5', 5-6', 6-7' #2, 6-7', 7-8', 8-9', 9-10', 10-11#2', 10-11', 11-12'#2, 11-12', 12-13', 13-14', 14-15', 15-16', 16-17', 17-18'