2.1.2 Mathematica

A grade: { 1, 2, 5, 6, 7, 8, 10, 11, 12, 13, 14, 16, 17, 18, 19, 20, 23, 24 }

B grade: { 3, 4, 9, 15, 21, 22 }

C grade: { }

F grade: { }