1-3 4-6 7-9 10-12 13-15 16-18 19-21 22-24 25-27 28-30 31-33 34-36 37-39 40-42 43-45 53-55 56-58 59-61 62-64 65-67 68-70 71-73 74-76 77-79 80-82
