import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class Main {
  public static void main(String[] args) throws IOException {
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    String s = in.readLine();
    int s_len = s.length();
    if(s.substring(0,(s_len-1)/2).equals(s.substring((s_len+1)/2,s_len))) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  }
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.IOException; IOException java.io public class Main {
  public static void main(String[] args) throws IOException {
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    String s = in.readLine();
    int s_len = s.length();
    if(s.substring(0,(s_len-1)/2).equals(s.substring((s_len+1)/2,s_len))) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  }
} Main public static void main(String[] args) throws IOException {
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    String s = in.readLine();
    int s_len = s.length();
    if(s.substring(0,(s_len-1)/2).equals(s.substring((s_len+1)/2,s_len))) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  } main {
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    String s = in.readLine();
    int s_len = s.length();
    if(s.substring(0,(s_len-1)/2).equals(s.substring((s_len+1)/2,s_len))) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  } BufferedReader in = new BufferedReader(new InputStreamReader(System.in)); in new BufferedReader(new InputStreamReader(System.in)) String s = in.readLine(); s in.readLine() in.readLine in int s_len = s.length(); s_len s.length() s.length s if(s.substring(0,(s_len-1)/2).equals(s.substring((s_len+1)/2,s_len))) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    } s.substring(0,(s_len-1)/2).equals(s.substring((s_len+1)/2,s_len)) s.substring(0,(s_len-1)/2).equals s.substring(0,(s_len-1)/2) s.substring s 0 (s_len-1)/2 (s_len-1) s_len 1 2 s.substring((s_len+1)/2,s_len) s.substring s (s_len+1)/2 (s_len+1) s_len 1 2 s_len {
      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 public class Main {
  public static void main(String[] args) throws IOException {
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    String s = in.readLine();
    int s_len = s.length();
    if(s.substring(0,(s_len-1)/2).equals(s.substring((s_len+1)/2,s_len))) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  }
} public class Main {
  public static void main(String[] args) throws IOException {
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    String s = in.readLine();
    int s_len = s.length();
    if(s.substring(0,(s_len-1)/2).equals(s.substring((s_len+1)/2,s_len))) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  }
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

public class Main {
  public static void main(String[] args) throws IOException {
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
    String s = in.readLine();
    int s_len = s.length();
    if(s.substring(0,(s_len-1)/2).equals(s.substring((s_len+1)/2,s_len))) {
      System.out.println("Yes");
    } else {
      System.out.println("No");
    }
  }
}