Catch The Value Of Cell

I want to catch the value of cell B25 in the Quantities sheet of the workbook Sales.xls in the variable marchSales.

The code is:

Sub marchSales()
Dim marchSales as Integer
With Workbooks("Sales").Worksheets("Quantities")
.Range("B25") = marchSales
End With

MsgBox "The sales of March is " & marchSales, vbInformation

End Sub

I am writing this code in the Ex9 sheet of the workbook Exercises.xls and both workbooks are in Drive D.