diff --git a/BST.py b/BST.py
index ddbe41f..7dbdff4 100644
--- a/BST.py
+++ b/BST.py
@@ -4,6 +4,15 @@ class BSTNode:
         self.left = None
         self.right = None
 
+    def size(self):
+        ls = 0
+        rs = 0
+        if self.left is not None:
+            ls = self.left.size()
+        if self.right is not None:
+            rs = self.right.size()
+        return rs + ls + 1
+
     def height(self):
         lh = 0
         rh = 0