2.1.7 Giac

A grade: { 2, 3, 4, 5, 6, 12, 13, 14, 15, 16, 20, 21, 22, 23, 24 }

B grade: { 1, 7, 8, 9, 10, 11, 17, 18, 19, 25, 26, 27, 28 }

C grade: { }

F grade: { 29, 30, 31, 32, 33, 34 }