Вычислить площадь круглой фигуры

Module Module1
 
    Sub Main()
        Dim Pi As Integer = 3.14
        Dim R As Integer = 0
        Dim A As Integer = 0
        Dim B As Integer = 0
        Console.WriteLine("=================================")
        Console.WriteLine("Write the radius of the circle:")
        R = Console.ReadLine
        Console.WriteLine("Write the length of the rectangle:")
        A = Console.ReadLine
        Console.WriteLine("Write the width of the rectangle:")
        B = Console.ReadLine
        Console.WriteLine("=================================")
        Console.WriteLine(vbCrLf & "=================================")
        Console.WriteLine("Perimeter circle = " & (Pi * (R ^ 2)) & ".")
        Console.WriteLine("Perimeter rectangle = " & (A * B) & ".")
        Console.WriteLine("=================================")
        If (A * B) > (Pi * (R ^ 2)) Then
            Console.WriteLine("Error perimeter rectangle > perimeter circle!")
        Else
            Console.WriteLine(vbCrLf & "=================================")
            Console.WriteLine("Perimeter circle = " & ((Pi * (R ^ 2)) - (A * B)) & ".")
            Console.WriteLine("=================================")
        End If
        Console.ReadLine()
    End Sub
 
End Module