import java.util.*;
class Main{
    public static void main(String[] args){
	Scanner stdIn = new Scanner(System.in);
	String S = stdIn.next();
	int N = S.length();
	String mae = S.substring(0,N/2);
	String ato = S.substring(N/2+1,N);
	if(mae.equals(ato)){
	    System.out.println("Yes");
	}else{
	    System.out.println("No");
	}
    }
} import java.util.*; util.* java class Main{
    public static void main(String[] args){
	Scanner stdIn = new Scanner(System.in);
	String S = stdIn.next();
	int N = S.length();
	String mae = S.substring(0,N/2);
	String ato = S.substring(N/2+1,N);
	if(mae.equals(ato)){
	    System.out.println("Yes");
	}else{
	    System.out.println("No");
	}
    }
} Main public static void main(String[] args){
	Scanner stdIn = new Scanner(System.in);
	String S = stdIn.next();
	int N = S.length();
	String mae = S.substring(0,N/2);
	String ato = S.substring(N/2+1,N);
	if(mae.equals(ato)){
	    System.out.println("Yes");
	}else{
	    System.out.println("No");
	}
    } main {
	Scanner stdIn = new Scanner(System.in);
	String S = stdIn.next();
	int N = S.length();
	String mae = S.substring(0,N/2);
	String ato = S.substring(N/2+1,N);
	if(mae.equals(ato)){
	    System.out.println("Yes");
	}else{
	    System.out.println("No");
	}
    } Scanner stdIn = new Scanner(System.in); stdIn new Scanner(System.in) String S = stdIn.next(); S stdIn.next() stdIn.next stdIn int N = S.length(); N S.length() S.length S String mae = S.substring(0,N/2); mae S.substring(0,N/2) S.substring S 0 N/2 N 2 String ato = S.substring(N/2+1,N); ato S.substring(N/2+1,N) S.substring S N/2+1 N/2 N 2 1 N if(mae.equals(ato)){
	    System.out.println("Yes");
	}else{
	    System.out.println("No");
	} mae.equals(ato) mae.equals mae ato {
	    System.out.println("Yes");
	} System.out.println("Yes") System.out.println System.out System System.out "Yes" {
	    System.out.println("No");
	} System.out.println("No") System.out.println System.out System System.out "No" String[] args args
import java.util.*;
class Main{
    public static void main(String[] args){
	Scanner stdIn = new Scanner(System.in);
	String S = stdIn.next();
	int N = S.length();
	String mae = S.substring(0,N/2);
	String ato = S.substring(N/2+1,N);
	if(mae.equals(ato)){
	    System.out.println("Yes");
	}else{
	    System.out.println("No");
	}
    }
}
