Sub UGvlookup()
Dim cl As Range, Dic As Object
Set Dic = CreateObject("Scripting.Dictionary"): Dic.Comparemode = vbTextCompare


With Sheets("Sheet A")
For Each cl In .Range("B2:B" & .Cells(Rows.count, "C").End(xlUp).Row)
    If Not Dic.exists(cl.Value) Then Dic.Add cl.Value, cl.Row
Next cl
End With
    With Sheets("Sheet B")
    For Each cl In .Range("A2:A" & .Cells(Rows.count, "A").End(xlUp).Row)
    If Dic.exists(cl.Value) Then
        Sheets("Latency").Cells(Dic(cl.Value), 17) = "UG"
    End If
If Dic.exists(cl.Value) Then
    Sheets("Latency").Cells(Dic(cl.Value), 17) = "UG"
    Dic.Remove (cl.Value)
End If
Next cl
End With