diff --git a/app/main.py b/app/main.py
index fa56336e..0fbfbd56 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1 +1,33 @@
-# write your code here
+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)
+
+    @staticmethod
+    def check_alive_animals() -> None:
+        Animal.alive = [animal for animal in Animal.alive if animal.health > 0]
+
+    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):
+    @staticmethod
+    def bite(herbivore: Herbivore) -> None:
+        if isinstance(herbivore, Herbivore) and herbivore.hidden is False:
+            herbivore.health -= 50
+            Animal.check_alive_animals()