2.1.3 Maple

A grade: { 3, 4, 7, 8, 12, 20, 21 }

B grade: { 1, 2, 5, 6, 9, 10, 11, 19, 24, 25, 28, 29 }

C grade: { }

F grade: { 13, 14, 15, 16, 17, 18, 22, 23, 26, 27 }