input: [0] C# keyword [1] abstract [2] as [3] base [4] bool [5] break [6] byte [8] catch [9] char [10] checked [11] class [12] const [13] continue [14] decimal [15] default [16] delegate [17] do [18] double [19] else [20] enum [21] event [22] explicit [7] 
output: case