diff --git a/app/__init__.py b/app/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/app/cafe.py b/app/cafe.py
new file mode 100644
index 00000000..5654a458
--- /dev/null
+++ b/app/cafe.py
@@ -0,0 +1,21 @@
+import datetime
+from app.errors import (NotVaccinatedError, NotWearingMaskError,
+                        OutdatedVaccineError)
+
+
+class Cafe:
+    def __init__(self, name: str) -> None:
+        self.name = name
+
+    def visit_cafe(self, visitor: dict) -> str:
+        if "vaccine" not in visitor:
+            raise NotVaccinatedError()
+
+        expiration_date = visitor["vaccine"]["expiration_date"]
+        if expiration_date < datetime.date.today():
+            raise OutdatedVaccineError()
+
+        if not visitor.get("wearing_a_mask", False):
+            raise NotWearingMaskError()
+
+        return f"Welcome to {self.name}"
diff --git a/app/errors.py b/app/errors.py
new file mode 100644
index 00000000..6f60eeac
--- /dev/null
+++ b/app/errors.py
@@ -0,0 +1,17 @@
+class VaccineError(Exception):
+    pass
+
+
+class NotVaccinatedError(VaccineError):
+    def __init__(self) -> None:
+        super().__init__("Visitor is not vaccinated.")
+
+
+class OutdatedVaccineError(VaccineError):
+    def __init__(self) -> None:
+        super().__init__("Visitor's vaccine is outdated.")
+
+
+class NotWearingMaskError(Exception):
+    def __init__(self) -> None:
+        super().__init__("Visitor is not wearing a mask.")
diff --git a/app/main.py b/app/main.py
index fa56336e..b82deb70 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1 +1,86 @@
-# write your code here
+from app.cafe import Cafe
+import datetime
+
+
+def go_to_cafe(friends: list[dict], cafe: Cafe) -> str:
+    masks_needed = 0
+    all_vaccinated = True
+
+    for friend in friends:
+        if "vaccine" not in friend:
+            all_vaccinated = False
+            continue
+
+        expiration_date = friend["vaccine"]["expiration_date"]
+        if expiration_date < datetime.date.today():
+            all_vaccinated = False
+
+        if not friend.get("wearing_a_mask", False):
+            masks_needed += 1
+
+    if not all_vaccinated:
+        return "All friends should be vaccinated"
+
+    if masks_needed > 0:
+        return f"Friends should buy {masks_needed} masks"
+
+    return f"Friends can go to {cafe.name}"
+
+
+# Example usage
+if __name__ == "__main__":
+    kfc = Cafe("KFC")
+
+    friends = [
+        {
+            "name": "Alisa",
+            "vaccine": {
+                "expiration_date": datetime.date.today()
+            },
+            "wearing_a_mask": True
+        },
+        {
+            "name": "Bob",
+            "vaccine": {
+                "expiration_date": datetime.date.today()
+            },
+            "wearing_a_mask": True
+        },
+    ]
+
+    print(go_to_cafe(friends, kfc))
+
+    friends = [
+        {
+            "name": "Alisa",
+            "vaccine": {
+                "expiration_date": datetime.date.today()
+            },
+            "wearing_a_mask": False
+        },
+        {
+            "name": "Bob",
+            "vaccine": {
+                "expiration_date": datetime.date.today()
+            },
+            "wearing_a_mask": False
+        },
+    ]
+
+    print(go_to_cafe(friends, kfc))
+
+    friends = [
+        {
+            "name": "Alisa",
+            "wearing_a_mask": True
+        },
+        {
+            "name": "Bob",
+            "vaccine": {
+                "expiration_date": datetime.date.today()
+            },
+            "wearing_a_mask": True
+        },
+    ]
+
+    print(go_to_cafe(friends, kfc))