diff --git a/src/CoveragePathPlanner/CoveragePathPlanner.cs b/src/CoveragePathPlanner/CoveragePathPlanner.cs
index 8bdf026..2a5b3e2 100644
--- a/src/CoveragePathPlanner/CoveragePathPlanner.cs
+++ b/src/CoveragePathPlanner/CoveragePathPlanner.cs
@@ -1,3 +1,4 @@
+using System;
 using System.Drawing;
 
 public class CoveragePathPlanner