
Imports System.Data
Imports System.Collections.Generic
Imports System.Xml.Linq
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 stationList_addIndex = StationList.Select(Function(x, index) New With {.station = x, .index = index})
        Dim stationlist_delLastItem = stationList_addIndex.Where(Function(x) x.index < stationList_addIndex.Count - 1)
        otherCompany = stationlist_delLastItem.Any(Function(x) Not x.station.Equals(stationList_addIndex.Where(Function(y) y.index = x.index + 1).First.station))
        If otherCompany Then
            Console.WriteLine("Yes")
        Else
            Console.WriteLine("No")
        End If
        Stop
    End Sub

End Module
