Module Module1
 
    Sub Main()
        Dim StationInputData As String = Console.ReadLine()
        Dim StationList As New List(Of String)
        For i As Integer = 0 To StationInputData.Length - 1
            StationList.Add(StationInputData.Substring(i, 1))
        Next
 
        Dim otherCompany As Boolean = False
 
        Dim preStation As String = String.Empty
        For Each station As String In StationList
            If preStation <> String.Empty AndAlso preStation <> station Then
                otherCompany = True
                Exit For
            End If
            preStation = station
        Next
 
        If otherCompany Then
            Console.WriteLine("Yes")
        Else
            Console.WriteLine("No")
        End If
        Stop
    End Sub
 
End Module