Need input box in working code

Hi I have below code thanks to Alphafrog, which works brilliant I need to insert a msg if some criteria is is not full filled.

Below is the working code and I need to insert this criteria.

Please have a look and see if you can help

Sincerely
Abjac

Creteria to be inserted in the code is

If .Cells(i, "A") = "758" And .Cells(i, "B") = "03" And .Cells(i, "P") = "" Then .
MsgBox "You need to insert the account name for country code 758 ledger 03"
Exit sub

Here is the code I would like to merge this criteria with.

Sub alphafrog()
    Dim i As Long, j As Long, arrEQ As Variant, iCell As Range
    
    'Number of Dots in cells E to Q
    arrEQ = Array(5, 8, 12, 2, 6, 6, 1, 1, 3, 11, 42, 35, 6)
    
    Sheets("Robot").Activate
    With Sheets("Robot")
        
        For i = 3 To .Cells(.Rows.Count, "A").End(xlUp).Row
        
            If WorksheetFunction.CountBlank(.Range("A" & i & ":AQ" & i)) <> 43 Then
            
                '32 dots in cell R
                If .Cells(i, "A") <> "" And .Cells(i, "B") = "03" Then
                    With .Cells(i, "R")
                        .Value = .Value & String(Application.Max(32 - Len(.Value), 0), ".")
                    End With
                End If
                
                'Cells E:Q (number of dots defined in arrEQ)
                For j = 0 To 12
                    With .Cells(i, "E").Offset(, j)
                        .Value = .Value & String(Application.Max(arrEQ(j) - Len(.Value), 0), ".")
                    End With
                Next j
                
                '3 dots in cells S:AQ
                For Each iCell In .Range("S" & i & ":AQ" & i)
                    iCell = iCell & String(Application.Max(3 - Len(iCell), 0), ".")
                Next iCell
                
            End If
        Next i
    End With
End Sub