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);

    }
} import java.util.*; util.* java 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);

    }
} 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);

    } main {
        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);

    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) String  moji = sc.nextLine(); moji sc.nextLine() sc.nextLine sc String moji2 = moji.substring(0,(moji.length()-1)/2); moji2 moji.substring(0,(moji.length()-1)/2) moji.substring moji 0 (moji.length()-1)/2 (moji.length()-1) moji.length() moji.length moji 1 2 String moji3 = moji.substring((moji.length()+1)/2,moji.length()); moji3 moji.substring((moji.length()+1)/2,moji.length()) moji.substring moji (moji.length()+1)/2 (moji.length()+1) moji.length() moji.length moji 1 2 moji.length() moji.length moji String flag = "No"; flag "No" if(moji2.equals(moji3)) flag = "Yes"; moji2.equals(moji3) moji2.equals moji2 moji3 flag = "Yes" flag "Yes" System.out.println(flag) System.out.println System.out System System.out flag String[] args args 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);

    }
} 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);

    }
} Main
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);

    }
}