diff --git a/app/main.py b/app/main.py
index fa56336e..f34395b8 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1 +1,40 @@
-# write your code here
+from __future__ import annotations
+
+
+class Animal:
+    alive = []
+
+    def __init__(
+            self,
+            name: str,
+            health: int = 100,
+            hidden: bool = False
+    ) -> None:
+        self.name = name
+        self.health = health
+        self.hidden = hidden
+        Animal.alive.append(self)
+
+    @classmethod
+    def remove_dead_animal(cls, animal: Herbivore) -> None:
+        cls.alive.remove(animal)
+
+    def __repr__(self) -> str:
+        return (f"{{Name: {self.name}, "
+                f"Health: {self.health}, "
+                f"Hidden: {self.hidden}}}")
+
+
+class Herbivore(Animal):
+
+    def hide(self) -> None:
+        self.hidden = not self.hidden
+
+
+class Carnivore(Animal):
+
+    def bite(self, target: Herbivore) -> None:
+        if (isinstance(target, Herbivore)) and (not target.hidden):
+            target.health -= 50
+            if target.health <= 0:
+                Animal.remove_dead_animal(target)