diff --git a/extra/project-euler/023/023.factor b/extra/project-euler/023/023.factor
index 7c28ebf..16d1f63 100644
--- a/extra/project-euler/023/023.factor
+++ b/extra/project-euler/023/023.factor
@@ -1,6 +1,7 @@
 ! Copyright (c) 2008 Aaron Schaefer.
 ! See http://factorcode.org/license.txt for BSD license.
-USING: kernel math math.ranges project-euler.common sequences sets sorting ;
+USING: assocs fry kernel math math.ranges project-euler.common sequences
+sets sorting ;
 IN: project-euler.023
 
 ! http://projecteuler.net/index.php?section=problems&id=23
@@ -42,10 +43,8 @@ IN: project-euler.023
     [1,b] [ abundant? ] filter ;
 
 : possible-sums ( seq -- seq )
-    dup { } -rot [
-        dupd [ + ] curry map
-        rot append prune swap rest
-    ] each drop natural-sort ;
+    dup H{ } clone
+    [ '[ [ + _ conjoin ] with each ] curry each ] keep keys ;