diff --git a/data_structures/binary_tree/segment_tree.py b/data_structures/binary_tree/segment_tree.py
index c7069b3f6..084fcf849 100644
--- a/data_structures/binary_tree/segment_tree.py
+++ b/data_structures/binary_tree/segment_tree.py
@@ -98,7 +98,7 @@ class SegmentTree:
 
     def show_data(self):
         show_list = []
-        for i in range(1, N + 1):
+        for i in range(1, self.N + 1):
             show_list += [self.query(i, i)]
         print(show_list)