Delete EntireRow if the data have different format on the range

Hi Everyone!

I have a problem with a macro.. I have a data format in ("A:R"), but I want a function to delete all the other cells/rows in case don't find the same format used in ("A:R")

In this function, I'm put "1", but this is not correct.

Sub AAA()
Dim LR As Long

    With ActiveSheet
        LR = .range("A1:R" & .Rows.Count).End(xlUp).Row
        If LR >= 1 Then .range("A" & LR).EntireRow.Delete
        End With
End Sub

How can I do?

Thank you!