2.1.7 Giac

A grade: { 1, 3, 5, 6, 10, 11, 12, 21, 22, 23 }

B grade: { 2, 17, 19, 20, 24, 26 }

C grade: { 4 }

F grade: { 7, 8, 9, 13, 14, 15, 16, 18, 25, 27, 28, 29, 30, 31, 32, 33, 34, 35 }