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..653a1843
--- /dev/null
+++ b/app/cafe.py
@@ -0,0 +1,22 @@
+import datetime
+from app.errors import (
+    NotVaccinatedError,
+    OutdatedVaccineError,
+    NotWearingMaskError
+)
+
+
+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("The visitor should be vaccinated.")
+        vaccine_expiration_date = visitor["vaccine"]["expiration_date"]
+        today = datetime.date.today()
+        if vaccine_expiration_date < today:
+            raise OutdatedVaccineError("Visitor's vaccine is outdated.")
+        if not visitor["wearing_a_mask"]:
+            raise NotWearingMaskError("All visitors should wear masks.")
+        return f"Welcome to {self.name}"
diff --git a/app/errors.py b/app/errors.py
new file mode 100644
index 00000000..fc10b078
--- /dev/null
+++ b/app/errors.py
@@ -0,0 +1,17 @@
+class VaccineError(Exception):
+    pass
+
+
+class NotVaccinatedError(VaccineError):
+    def __init__(self, message: str) -> None:
+        self.message = message
+
+
+class OutdatedVaccineError(VaccineError):
+    def __init__(self, message: str) -> None:
+        self.message = message
+
+
+class NotWearingMaskError(Exception):
+    def __init__(self, message: str) -> None:
+        self.message = message
diff --git a/app/main.py b/app/main.py
index fa56336e..76ff2cd1 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1 +1,17 @@
-# write your code here
+from app.errors import NotWearingMaskError, VaccineError
+from app.cafe import Cafe
+
+
+def go_to_cafe(friends: list, cafe: Cafe) -> str:
+    masks_to_buy = 0
+    for friend in friends:
+        try:
+            cafe.visit_cafe(friend)
+        except VaccineError:
+            return "All friends should be vaccinated"
+        except NotWearingMaskError:
+            masks_to_buy += 1
+    if masks_to_buy > 0:
+        return f"Friends should buy {masks_to_buy} masks"
+    else:
+        return f"Friends can go to {cafe.name}"