diff --git a/src/blackbox/calculator.py b/src/blackbox/calculator.py
index a99a584..51cd658 100644
--- a/src/blackbox/calculator.py
+++ b/src/blackbox/calculator.py
@@ -6,16 +6,16 @@ from blackbox.blackbox import Blackbox
 class Calculator(Blackbox):
     
     """This class just for example, it show how to implement Blackbox interface."""
-    
+
     def valid(self, data: any) -> bool:
-        return isinstance(data, dict) and "operation" in data and "a" in data and "b" in data
+        return isinstance(data, dict) and "op" in data and "left" in data and "right" in data
     
     def processing(self, data: dict) -> any:
         if not self.valid(data):
             raise ValueError("Invalid data")
-        a = data["a"]
-        b = data["b"]
-        op = data["operation"]
+        a = data["left"]
+        b = data["right"]
+        op = data["op"]
         if op == "add":
             return a + b
         if op == "sub":