module practiceA
  sub Main(ByVal args() as String)
    	Dim arr as string
    	Dim kekka as string
    	arr=Console.ReadLine()
    
     	If arr.Substring(0, (arr.Length - 1) / 2) = arr.Substring((arr.Length + 3) / 2 - 1, arr.Length - (arr.Length + 3) / 2 + 1) Then
            kekka = "Yes"
        Else
            kekka = "No"
        End If
         
Console.WriteLine(kekka)

  end sub
end module