2.1.3 Maple

A grade: { 1, 3, 4, 5, 10, 12, 20, 21, 22, 23, 25, 27, 30, 32, 33, 34, 35 }

B grade: { 2, 11, 17, 19, 24, 26 }

C grade: { 6, 7, 8, 13, 14 }

F grade: { 9, 15, 16, 18, 28, 29, 31 }