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diff --git a/H58.hs b/H58.hs
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+import Tree
+import H55
+import H56
+
+symCbalTrees n
+    | n `mod` 2 == 0 = []
+    | otherwise = [Branch 'x' x (reverseTree x) | x <- cbalTree (n `div` 2)]
+
+reverseTree Empty = Empty
+reverseTree (Branch x l r) = Branch x (reverseTree r) (reverseTree l)
+
+symCbalTrees' = filter symmetric . cbalTree