Count in a row until content changes, then count this next content until it changes and so on

Jungdra 

Create the following custom VBA function:

Function CountLetters(rng As Range) As String
    Dim i As Long
    Dim s As String
    Dim c As String
    Dim n As Long
    
    c = rng(1).Value
    For i = 1 To rng.Count
        If rng(i).Value = c Then
            n = n + 1
        Else
            If i > 1 Then
                s = s & ", " & n & "x" & c
            End If
            c = rng(i).Value
            n = 1
        End If
    Next i
    s = s & ", " & n & "x" & c
    CountLetters = Mid(s, 3)
End Function

Let's say the first row with letters is A2:O2.

Enter the following formula in P2:

=CountLetters(A2:O2)

Fill down to the last row with letters.