diff --git a/intervaltree/intervaltree.py b/intervaltree/intervaltree.py
index 6bd1b8e..4ab6fdb 100644
--- a/intervaltree/intervaltree.py
+++ b/intervaltree/intervaltree.py
@@ -818,7 +818,7 @@ def begin(self):
         """
         Returns the lower bound of the first interval in the tree.
         
-        Completes in O(n) time.
+        Completes in O(1) time.
         """
         if not self.boundary_table:
             return 0
@@ -828,7 +828,7 @@ def end(self):
         """
         Returns the upper bound of the last interval in the tree.
         
-        Completes in O(n) time.
+        Completes in O(1) time.
         """
         if not self.boundary_table:
             return 0