2.1.7 Giac

A grade: { 2, 6, 10, 14, 15, 16, 17, 18, 19, 20, 21, 22, 24, 25, 26, 28, 33, 34, 35, 36, 40, 43, 47, 48, 49, 50 }

B grade: { 1, 4, 7, 8, 9, 12, 13, 27, 29, 30, 31, 32, 37, 41, 42, 44 }

C grade: { }

F grade: { 3, 5, 11, 23, 38, 39, 45, 46 }