diff --git a/anikinvd/docs/data/1-st-exercise/phonebook.py b/anikinvd/docs/data/1-st-exercise/phonebook.py
index 3296d3f..3480c11 100644
--- a/anikinvd/docs/data/1-st-exercise/phonebook.py
+++ b/anikinvd/docs/data/1-st-exercise/phonebook.py
@@ -85,13 +85,79 @@ def ht_get_all(table):
     return all_entries
 
 
+def bst_create_node(name, phone):
+    return {'name': name, 'phone': phone, 'left': None, 'right': None}
+
+
+def bst_insert(root, name, phone):
+    if root is None:
+        return bst_create_node(name, phone)
+    if name == root['name']:
+        root['phone'] = phone
+    elif name < root['name']:
+        root['left'] = bst_insert(root['left'], name, phone)
+    else:
+        root['right'] = bst_insert(root['right'], name, phone)
+    return root
+
+
+def bst_find(root, name):
+    if root is None:
+        return None
+    if name == root['name']:
+        return root['phone']
+    elif name < root['name']:
+        return bst_find(root['left'], name)
+    else:
+        return bst_find(root['right'], name)
+
+
+def bst_find_min(node):
+    while node['left'] is not None:
+        node = node['left']
+    return node
+
+
+def bst_delete(root, name):
+    if root is None:
+        return None
+    if name < root['name']:
+        root['left'] = bst_delete(root['left'], name)
+    elif name > root['name']:
+        root['right'] = bst_delete(root['right'], name)
+    else:
+        if root['left'] is None:
+            return root['right']
+        if root['right'] is None:
+            return root['left']
+        min_node = bst_find_min(root['right'])
+        root['name'] = min_node['name']
+        root['phone'] = min_node['phone']
+        root['right'] = bst_delete(root['right'], min_node['name'])
+    return root
+
+
+def bst_inorder_collect(root, out_list):
+    if root is not None:
+        bst_inorder_collect(root['left'], out_list)
+        out_list.append((root['name'], root['phone']))
+        bst_inorder_collect(root['right'], out_list)
+
+
+def bst_get_all(root):
+    result = []
+    bst_inorder_collect(root, result)
+    return result
+
+
 if __name__ == '__main__':
-    table = ht_create()
-    ht_insert(table, "Alice", "111-222")
-    ht_insert(table, "Bob", "333-444")
-    ht_insert(table, "Alice", "555-666")
-    print(ht_find(table, "Alice"))
-    print(ht_find(table, "Bob"))
-    print(ht_find(table, "Charlie"))
-    ht_delete(table, "Bob")
-    print(ht_get_all(table))
\ No newline at end of file
+    root = None
+    root = bst_insert(root, "Charlie", "111-111")
+    root = bst_insert(root, "Alice", "222-222")
+    root = bst_insert(root, "Bob", "333-333")
+    root = bst_insert(root, "Alice", "444-444")
+    print(bst_find(root, "Alice"))
+    print(bst_find(root, "Bob"))
+    print(bst_get_all(root))
+    root = bst_delete(root, "Bob")
+    print(bst_get_all(root))
\ No newline at end of file