diff --git a/app/main.py b/app/main.py
index 626f41cf..267ea138 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1,34 +1,74 @@
 class Deck:
-    def __init__(self, row, column, is_alive=True):
-        pass
+    def __init__(self, row: int, column: int, is_alive: bool = True) -> None:
+        self.row = row
+        self.column = column
+        self.is_alive = is_alive
 
 
 class Ship:
-    def __init__(self, start, end, is_drowned=False):
+    def __init__(self, start: tuple,
+                 end: tuple,
+                 is_drowned: bool = False) -> None:
         # Create decks and save them to a list `self.decks`
-        pass
+        self.is_drowned = is_drowned
+        self.decks = []
 
-    def get_deck(self, row, column):
+        r1, c1 = start
+        r2, c2 = end
+
+        if r1 == r2:
+            for col in range(min(c1, c2), max(c1, c2) + 1):
+                self.decks.append(Deck(r1, col))
+
+        elif c1 == c2:
+            for row in range(min(r1, r2), max(r1, r2) + 1):
+                self.decks.append(Deck(row, c1))
+
+        else:
+            raise ValueError("Ship must be horizontal or vertical")
+
+    def get_deck(self, row: int, column: int) -> Deck | None:
         # Find the corresponding deck in the list
-        pass
+        for deck in self.decks:
+            if deck.row == row and deck.column == column:
+                return deck
+        return None
 
-    def fire(self, row, column):
+    def fire(self, row: int, column: int) -> str:
         # Change the `is_alive` status of the deck
         # And update the `is_drowned` value if it's needed
-        pass
+        deck = self.get_deck(row, column)
+        if deck is None or not deck.is_alive:
+            return "Miss!"
+
+        deck.is_alive = False
+        if all(not d.is_alive for d in self.decks):
+            self.is_drowned = True
+            return "Sunk!"
+
+        return "Hit!"
 
 
 class Battleship:
-    def __init__(self, ships):
+    def __init__(self, ships: list[Ship]) -> None:
         # Create a dict `self.field`.
         # Its keys are tuples - the coordinates of the non-empty cells,
         # A value for each cell is a reference to the ship
         # which is located in it
-        pass
+        self.field = {}
+
+        for start, end in ships:
+            ship = Ship(start, end)
+            for deck in ship.decks:
+                self.field[(deck.row, deck.column)] = ship
 
-    def fire(self, location: tuple):
+    def fire(self, location: tuple) -> str:
         # This function should check whether the location
         # is a key in the `self.field`
         # If it is, then it should check if this cell is the last alive
         # in the ship or not.
-        pass
+        if location not in self.field:
+            return "Miss!"
+        ship = self.field[location]
+        row, column = location
+        return ship.fire(row, column)