VBA Code To Automatically Fill Down And Apply Formula Till Last Cell

I am using this code and it works fine:

Dim MyData As Range
Dim MyResult As Range
Set MyData = Range("E1:E1000000")
Set MyData2 = Range("F1:F1000000")
Set MyResult = Range("J4")
MyResult.Select
Selection.Formula = "=COUNTIFS(" & MyData.Address & ",""=Kim""," & MyData2.Address & ",""=done"" )"

Is there any way I can change the code so that it automatically finds the last cell as Im using Range("E1:E1000000") and Range("F1:F1000000") because there will not be more than 1000000 entries.