A grade: { 1, 3, 4, 5, 6, 7, 10, 11, 13, 14, 15, 16, 17, 18, 19, 20, 21, 23, 26, 27, 28, 29, 31, 32, 33, 39, 40, 41, 42, 43, 44, 46, 47, 49, 59, 60, 61, 62, 63, 64 }
B grade: { 8, 9, 12, 22, 30, 34, 38, 45, 50 }
C grade: { 2, 24, 25, 35, 36, 37, 48, 51, 52, 53, 54, 55, 56, 57, 58 }
F grade: { }