1 files changed, 1 insertions, 1 deletions
diff --git a/Day3.cs b/Day3.cs
index 9049b7a..6bdf8ea 100644
--- a/Day3.cs
+++ b/Day3.cs
@@ -4,7 +4,7 @@ using System.Linq;
 
 namespace aoc2019
 {
-    internal class Day3 : Day
+    internal sealed class Day3 : Day
     {
         public override int DayNumber => 3;