A grade: { 2, 4, 5, 6, 7, 9, 11, 13, 14, 17, 19, 20, 21, 22, 24, 26, 27, 28, 29, 30, 31, 35, 36, 40, 41, 45, 46, 50, 51, 54, 55, 56, 60, 61, 64, 65, 66, 69, 70, 71, 72 }
B grade: { }
C grade: { 12, 15, 73, 74, 76, 79, 80, 82 }
F grade: { 1, 3, 8, 10, 16, 18, 23, 25, 32, 33, 34, 37, 38, 39, 42, 43, 44, 47, 48, 49, 52, 53, 57, 58, 59, 62, 63, 67, 68, 75, 77, 78, 81, 83, 84 }