I'm trying to create a simple function

CREATE FUNCTION Add2Numbers (@X INT, @Y INT)
RETURNS INT
AS
BEGIN
   DECLARE @Z INT
   SET @Z = @X + @Y
   RETURN(@Z)
END

Getting error:
"Error 170: Line1: Incorrect syntax near 'FUNCTION'.
Must declare the variable '@X'.
A RETURN statement with a return value cannot be used in this context."