Implemented C# index operator (didn't even know it was a thing).

Program.cs

@@ -67,7 +67,7 @@ namespace SBT_Downloader
                 var chapterTokens = urlTokens.Last().Split("_").ToList();
                 chapterTokens.RemoveRange(0,5);
                 string chapterLastToken = chapterTokens.Last().Split(".").First();
-                chapterTokens[chapterTokens.Count - 1] = chapterLastToken;
+                chapterTokens[^1] = chapterLastToken;
                 chapters.Add(string.Join(" ", chapterTokens));
             }