diff --git a/lab6/Makefile b/lab6/Makefile
index ae7de68..363b63a 100644
--- a/lab6/Makefile
+++ b/lab6/Makefile
@@ -1,4 +1,4 @@
-.PHONY: run build clean task1 build-task1 clean-task1 task2 build-task2 clean-task2 task3 build-task3 clean-task3 task4 build-task4 clean-task4 task5 build-task5 clean-task5
+.PHONY: run build clean task1 build-task1 clean-task1 task2 build-task2 clean-task2 task3 build-task3 clean-task3 task4 build-task4 clean-task4 task5 build-task5 clean-task5 task6 build-task6 clean-task6
 
 # task1
 run:
@@ -61,3 +61,13 @@ build-task5:
 
 clean-task5:
 	cd task5 && dotnet clean
+
+# task6
+task6:
+	cd task6 && dotnet run --project task6.fsproj
+
+build-task6:
+	cd task6 && dotnet build
+
+clean-task6:
+	cd task6 && dotnet clean
diff --git a/lab6/task6/Program.fs b/lab6/task6/Program.fs
new file mode 100644
index 0000000..6565a53
--- /dev/null
+++ b/lab6/task6/Program.fs
@@ -0,0 +1,161 @@
+module Task6
+
+open System
+
+type BinaryTree =
+    | Empty
+    | Node of string * BinaryTree * BinaryTree
+
+let empty = Empty
+
+let rec insert value tree =
+    match tree with
+    | Empty -> Node(value, Empty, Empty)
+    | Node(v, left, right) ->
+        if value < v then
+            Node(v, insert value left, right)
+        elif value > v then
+            Node(v, left, insert value right)
+        else
+            tree
+
+let rec contains value tree =
+    match tree with
+    | Empty -> false
+    | Node(v, left, right) ->
+        if value = v then true
+        elif value < v then contains value left
+        else contains value right
+
+let rec findMin tree =
+    match tree with
+    | Empty -> None
+    | Node(v, Empty, _) -> Some v
+    | Node(_, left, _) -> findMin left
+
+let rec findMax tree =
+    match tree with
+    | Empty -> None
+    | Node(v, _, Empty) -> Some v
+    | Node(_, _, right) -> findMax right
+
+let rec remove value tree =
+    match tree with
+    | Empty -> Empty
+    | Node(v, left, right) ->
+        if value < v then
+            Node(v, remove value left, right)
+        elif value > v then
+            Node(v, left, remove value right)
+        else
+            match left, right with
+            | Empty, Empty -> Empty
+            | Empty, right -> right
+            | left, Empty -> left
+            | left, right ->
+                match findMin right with
+                | Some minValue ->
+                    Node(minValue, left, remove minValue right)
+                | None -> left
+
+let rec inOrder tree =
+    match tree with
+    | Empty -> []
+    | Node(v, left, right) ->
+        (inOrder left) @ [v] @ (inOrder right)
+
+let rec preOrder tree =
+    match tree with
+    | Empty -> []
+    | Node(v, left, right) ->
+        [v] @ (preOrder left) @ (preOrder right)
+
+let rec postOrder tree =
+    match tree with
+    | Empty -> []
+    | Node(v, left, right) ->
+        (postOrder left) @ (postOrder right) @ [v]
+
+let rec height tree =
+    match tree with
+    | Empty -> 0
+    | Node(_, left, right) ->
+        1 + max (height left) (height right)
+
+let rec size tree =
+    match tree with
+    | Empty -> 0
+    | Node(_, left, right) ->
+        1 + (size left) + (size right)
+
+let rec map f tree =
+    match tree with
+    | Empty -> Empty
+    | Node(v, left, right) ->
+        Node(f v, map f left, map f right)
+
+let rec fold f acc tree =
+    match tree with
+    | Empty -> acc
+    | Node(v, left, right) ->
+        let leftAcc = fold f acc left
+        let nodeAcc = f leftAcc v
+        fold f nodeAcc right
+
+let rec filter predicate tree =
+    match tree with
+    | Empty -> Empty
+    | Node(v, left, right) ->
+        let filteredLeft = filter predicate left
+        let filteredRight = filter predicate right
+        if predicate v then
+            Node(v, filteredLeft, filteredRight)
+        else
+            let leftList = inOrder filteredLeft
+            let rightList = inOrder filteredRight
+            let combinedList = leftList @ rightList
+            List.fold (fun acc x -> insert x acc) Empty combinedList
+
+let fromList lst =
+    List.fold (fun acc x -> insert x acc) Empty lst
+
+let toList tree = inOrder tree
+
+[<EntryPoint>]
+let main argv =
+    let tree1 = empty
+                |> insert "dog"
+                |> insert "cat"
+                |> insert "elephant"
+                |> insert "bird"
+                |> insert "fish"
+    
+    printfn "Tree contents (in-order): %A" (inOrder tree1)
+    printfn "Tree contents (pre-order): %A" (preOrder tree1)
+    printfn "Tree contents (post-order): %A" (postOrder tree1)
+    
+    printfn "Contains 'cat': %b" (contains "cat" tree1)
+    printfn "Contains 'zebra': %b" (contains "zebra" tree1)
+    
+    printfn "Min value: %A" (findMin tree1)
+    printfn "Max value: %A" (findMax tree1)
+    
+    printfn "Tree height: %d" (height tree1)
+    printfn "Tree size: %d" (size tree1)
+    
+    let tree2 = remove "cat" tree1
+    printfn "After removing 'cat': %A" (inOrder tree2)
+    
+    let upperTree = map (fun s -> s.ToUpper()) tree1
+    printfn "Uppercase tree: %A" (inOrder upperTree)
+    
+    let longWords = filter (fun s -> s.Length > 3) tree1
+    printfn "Words longer than 3 chars: %A" (inOrder longWords)
+    
+    let wordCount = fold (fun acc _ -> acc + 1) 0 tree1
+    printfn "Word count using fold: %d" wordCount
+    
+    let listTree = fromList ["apple"; "banana"; "cherry"; "date"]
+    printfn "Tree from list: %A" (toList listTree)
+    
+    0
\ No newline at end of file
diff --git a/lab6/task6/task6.fsproj b/lab6/task6/task6.fsproj
new file mode 100644
index 0000000..1cddbd7
--- /dev/null
+++ b/lab6/task6/task6.fsproj
@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net7.0</TargetFramework>
+  </PropertyGroup>
+
+</Project>
\ No newline at end of file