diff --git a/app/main.py b/app/main.py
index fa56336e..39054e9a 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1 +1,39 @@
-# write your code here
+from typing import Any
+
+
+class Animal:
+    alive = []
+
+    def __init__(self, name: str, health: int = 100,
+                 hidden: bool = False, *args: Any) -> None:
+        self.name = name
+        self.health = health
+        self.hidden = hidden
+        Animal.alive.append(self)
+
+    def die(self) -> None:
+        if self in Animal.alive:
+            Animal.alive.remove(self)
+
+    def __repr__(self) -> str:
+        return (f"{{Name: {self.name}, "
+                f"Health: {self.health}, "
+                f"Hidden: {self.hidden}}}")
+
+    def __str__(self) -> str:
+        return str([repr(animal) for animal in Animal.alive])
+
+
+class Herbivore(Animal):
+    def hide(self) -> None:
+        self.hidden = not self.hidden
+
+
+class Carnivore(Animal):
+    def bite(self, prey: Animal) -> None:
+        if (isinstance(prey, Herbivore)
+                and not prey.hidden
+                and prey in Animal.alive):
+            prey.health -= 50
+            if prey.health <= 0:
+                prey.die()