Dim aData()    Dim LastRowForecast As Long
    Dim i As Long
     
    LastRowForecast = ...
    aData = Range("AI39:AI" & LastRowForecast).Value
     
    For i = 1 To UBound(aData)
        aData(i, 1) = UCase(Left(aData(i, 1),1)) & LCase(Mid(aData(i, 1), 2))
    Next i
    Range("AI39:AI" & LastRowForecast).Value = aData

For X = 39 To LastRowForecast    
    Dim strData As String
    strData = Range("AI" & X).Value
    strData = UCase(Left(strData, 1)) & LCase(Mid(strData, 2))
    Range("AI" & X).Value = strData
Next X

ReDim arrFullSales(1 To CountOfRowByGroups, 1 To NumberOfMonths) As Double

Q = 1
For X = 1 To CountOfRowByGroups
    For y = Q To CountOfRow
        If arrSalesGroupBySalesChanel(y, 1) = CollSalesGroupBySalesChanel.Item(X) Then
            For Z = 1 To NumberOfMonths
                arrFullSales(X, Z) = arrFullSales(X, Z) + arrFullSalesBasic(y, Z)
            Next Z
        End If
    Next y
    Q = Q + 1
Next X

H = 2
For x = 2 To CountOfRow
    For y = 2 To DaysOfModeling + 1
         ThisWorkbook.Sheets("Динамика запасов").Cells(H, 1) = arrStockByDay(x, 1)
         ThisWorkbook.Sheets("Динамика запасов").Cells(H, 2) = arrStockByDay(1, y)
         ThisWorkbook.Sheets("Динамика запасов").Cells(H, 3) = arrStockByDay(x, y)
         H = H + 1
    Next
Next