diff --git a/VolkovVA/cod.py b/VolkovVA/cod.py
index 605787b..971551c 100644
--- a/VolkovVA/cod.py
+++ b/VolkovVA/cod.py
@@ -101,4 +101,112 @@ def ht_list_all(buckets):
         while current is not None:
             res += [(current['name'], current['phone'])]
             current = current['next']
-    return sort_records(res)
\ No newline at end of file
+    return sort_records(res)
+
+
+
+
+
+def bst_insert(root, name, phone):
+    new_node = {'name': name, 'phone': phone, 'left': None, 'right': None}
+    
+    if root is None:
+        return new_node
+        
+    current = root
+    while True:
+        if name == current['name']:
+            current['phone'] = phone  
+            break
+        elif name < current['name']:
+            if current['left'] is None:
+                current['left'] = new_node
+                break
+            current = current['left']
+        else:
+            if current['right'] is None:
+                current['right'] = new_node
+                break
+            current = current['right']
+            
+    return root
+
+
+def bst_find(root, name):
+    current = root
+    while current is not None:
+        if name == current['name']:
+            return current['phone']
+        elif name < current['name']:
+            current = current['left']
+        else:
+            current = current['right']
+    return None
+
+
+def bst_delete(root, name):
+    if root is None:
+        return None
+        
+    p_node = None
+    current = root
+    
+    while current is not None and current['name'] != name:
+        p_node = current
+        if name < current['name']:
+            current = current['left']
+        else:
+            current = current['right']
+            
+    if current is None:
+        return root
+        
+    if current['left'] is None and current['right'] is None:
+        if p_node is None:
+            return None
+        if p_node['left'] is current:
+            p_node['left'] = None
+        else:
+            p_node['right'] = None
+        return root
+
+    if current['left'] is None:
+        c_node = current['right']
+    elif current['right'] is None:
+        c_node = current['left']
+    else:
+        succ_parent = current
+        succ = current['right']
+        while succ['left']:
+            succ_parent = succ
+            succ = succ['left']
+            
+        current['name'], current['phone'] = succ['name'], succ['phone']
+        
+        if succ_parent['left'] is succ:
+            succ_parent['left'] = succ['right']
+        else:
+            succ_parent['right'] = succ['right']
+        return root
+        
+    if p_node is None:
+        return c_node
+    if p_node['left'] is current:
+        p_node['left'] = c_node
+    else:
+        p_node['right'] = c_node
+    return root
+
+
+def bst_list_all(root):
+    record = []
+    
+    def helper(node):
+        if node is not None:
+            helper(node['left'])
+            nonlocal record
+            record += [(node['name'], node['phone'])]
+            helper(node['right'])
+            
+    helper(root)
+    return record
\ No newline at end of file