import java.util.*;

public class Main {
	public static void main (String[] args) {
		Scanner in = new Scanner(System.in);
		String N = in.next();
        String w1 = N.substring(0, N.length()/2 );
        String w2 = N.substring(N.length()/2, N.length() );

        if(w1.equals(w2)){
    		System.out.println("Yes");            
        }else{
    		System.out.println("No");
        }
   }

}