diff --git a/extra/project-euler/046/046.factor b/extra/project-euler/046/046.factor
index e4b8dcc955..0aa9eafe58 100755
--- a/extra/project-euler/046/046.factor
+++ b/extra/project-euler/046/046.factor
@@ -1,6 +1,7 @@
 ! Copyright (c) 2008 Aaron Schaefer.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: kernel math math.functions math.primes math.ranges sequences project-euler.common ;
+USING: kernel math math.functions math.primes math.ranges
+sequences project-euler.common math.bitwise ;
 IN: project-euler.046
 
 ! http://projecteuler.net/index.php?section=problems&id=46