diff --git a/src/Cylinder.cc b/src/Cylinder.cc
index a5a11ac5..af8103e0 100644
--- a/src/Cylinder.cc
+++ b/src/Cylinder.cc
@@ -1,4 +1,4 @@
-not#include <filesystem>
+#include <filesystem>
 #include <iostream>
 #include <iomanip>
 #include <sstream>