diff --git a/app/main.py b/app/main.py
index fa56336e..6b7f2351 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1 +1,32 @@
-# write your code here
+class Animal:
+    hidden = False
+    alive = []
+
+    def __init__(self, name: str, health: int = 100) -> None:
+        self.name = name
+        self.health = health
+        Animal.alive.append(self)
+
+    def __len__(self) -> int:
+        return len(Animal.alive)
+
+    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):
+    @classmethod
+    def bite(cls, goal: Animal) -> None:
+        if isinstance(goal, Herbivore) and not goal.hidden:
+            goal.health -= 50
+            if goal.health <= 0:
+                Animal.alive.remove(goal)