diff --git a/app/main.py b/app/main.py
index fa56336e..228b0350 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) -> None:
+        self.name = name
+        self.health = health
+        self.hidden = False
+        self.alive.append(self)
+
+    def __repr__(self) -> str:
+        return (
+            f"{{Name: {self.name}, Health: "
+            f"{self.health}, Hidden: {self.hidden}}}"
+        )
+
+
+class Herbivore(Animal):
+
+    def hide(self) -> None:
+        if not self.hidden:
+            self.hidden = True
+        else:
+            self.hidden = False
+
+
+class Carnivore(Animal):
+
+    @staticmethod
+    def bite(herbivore: Herbivore) -> None:
+        if isinstance(herbivore, Herbivore) and not herbivore.hidden:
+            herbivore.health -= 50
+        if herbivore.health <= 0:
+            Animal.alive.remove(herbivore)