2.1.2 Mathematica

A grade: { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 17, 18, 19, 20, 22, 27, 28, 29, 30, 31, 33, 34, 35, 36, 37, 41, 42, 43, 44, 45, 46, 47, 48, 49 }

B grade: { 13, 21, 32, 38, 39, 40 }

C grade: { 16, 23, 24, 25, 26 }

F grade: { }