Sub HighlightDuplicates()
    Dim lastRow As Long
    Dim lastCol As Long
    Dim rng As Range
    Dim cell As Range
    Dim dict As Object
    
    ' Find the last row with data in column A
    lastRow = Cells(Rows.Count, "A").End(xlUp).Row
    
    ' Find the last column with data in the range
    lastCol = Cells(1, Columns.Count).End(xlToLeft).Column
    
    ' Define the range of data
    Set rng = Range("A2").Resize(lastRow - 1, lastCol) ' Assuming data is in columns A to lastCol
    
    ' Create a dictionary object to store unique values
    Set dict = CreateObject("Scripting.Dictionary")
    
    ' Loop through each cell in the range
    For Each cell In rng.Columns(1).Cells ' Only consider the first column (Number column)
        If dict.exists(cell.Value) Then
            ' Highlight the cells until the last column if the value is a duplicate
            For Each c In Range(cell, Cells(cell.Row, lastCol))
                If c.Value <> "" Then ' Check if cell contains data
                    c.Interior.Color = RGB(255, 0, 0) ' Red color
                End If
            Next c
        Else
            ' Add the value to the dictionary if it's not a duplicate
            dict(cell.Value) = 1
        End If
    Next cell
End Sub