import java.util.*;
public class Main{
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String  moji = sc.nextLine();
        String moji2 = moji.substring(0,(moji.length()-1)/2);
        String moji3 = moji.substring((moji.length()+1)/2,moji.length());

        //System.out.println(moji2);
        //System.out.println(moji3);

        String flag = "No";

        if(moji2.equals(moji3)) flag = "Yes";
        System.out.println(flag);

    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz