diff --git a/examples/tetris/src/gui.d b/examples/tetris/src/gui.d
index b29b763a..27997bf6 100644
--- a/examples/tetris/src/gui.d
+++ b/examples/tetris/src/gui.d
@@ -3,6 +3,7 @@ module gui;
 import model;
 
 import dlangui;
+import std.algorithm;
 
 /// game action codes
 enum TetrisAction : int {