2.1.3 Maple

A grade: { 1, 2, 3, 4, 6, 7, 8, 9, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 27, 30, 32, 33 }

B grade: { 28, 29, 31 }

C grade: { 11, 12, 13, 25, 26 }

F grade: { 5, 10 }