import Foundation

let str = readLine()!
let number = str.characters.count
let num = (number - 1) / 2
let start1 = str.startIndex
let end1 =  str.index(str.startIndex, offsetBy:(num))
let start2 = str.index((num + 1), offsetBy:(num))
let end2 = str.endIndex

let str1 = str[start1...end1]
let str2 = str[start2...end2]
if (str1 == str2){
  print("Yes")
}else{
  print("No")
}