diff --git a/DataStructures/Trees/RedBlack.fs b/DataStructures/Trees/RedBlack.fs
index 3946f30..1b41264 100644
--- a/DataStructures/Trees/RedBlack.fs
+++ b/DataStructures/Trees/RedBlack.fs
@@ -5,5 +5,24 @@ module RedBlack =
     type Color = Red | Black
 
     type RedBlackTree<'T> =
-        | Node of Color * 'T RedBlackTree * 'T * 'T RedBlackTree
-        | Leaf
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+        | Node of Color * Left: 'T RedBlackTree * Value: 'T * Right: 'T RedBlackTree
+        | Leaf
+
+    let balance = function
+        | Black, Node (Red, Node (Red, a, x, b), y, c), z, d
+        | Black, Node (Red, a, x, Node (Red, b, y, c)), z, d
+        | Black, a, x, Node (Red, Node (Red, b, y, c), z, d)
+        | Black, a, x, Node (Red, b, y, Node (Red, c, z, d)) ->
+            Node (Red, Node (Black, a, x, b), y, Node (Black, c, z, d))
+        | a, b, c, d -> Node (a, b, c, d)
+
+    let insert x s =
+        let rec loop = function
+            | Leaf -> Node (Red, Leaf, x, Leaf)
+            | Node (color, a, y, b) as s ->
+                if x < y then balance (color, loop a, y, b)
+                elif y < x then balance (color, a, y, loop b)
+                else s
+
+        loop s
+        
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