public class MMM {
    public static void main(String[] args) {
        DLNode ff = createDLNode(1);
          DLNode neww = createDLNode(2);
          ff = addFirst(ff, neww);
          neww = createDLNode(2);
          ff = addFirst(ff, neww);
          neww = createDLNode(3);
          ff = addFirst(ff, neww);
          neww = createDLNode(4);
          ff = addFirst(ff, neww);
          neww = createDLNode(2);
          ff = addFirst(ff, neww);
          neww = createDLNode(5);
          ff = addFirst(ff, neww);
          neww = createDLNode(5);
          ff = addFirst(ff, neww);
          neww = createDLNode(5);
          ff = addFirst(ff, neww);
          neww = createDLNode(5);
          ff = addFirst(ff, neww);
          neww = createDLNode(2);
          ff = addFirst(ff, neww);
          neww = createDLNode(5);
          ff = addFirst(ff, neww);
          neww = createDLNode(5);
          ff = addFirst(ff, neww);
          neww = createDLNode(5);
          ff = addFirst(ff, neww);
          printList(ff);

          ff = deleteNotPrime(ff);
          System.out.println("Delete not prime");
          printList(ff);
          }

    public static DLNode addFirst(DLNode h, DLNode newNode) {
          if(newNode == null) return h;

          newNode.prev = null;
          newNode.next = h;
          if (h != null) {
            h.prev = newNode;
          }
          return newNode;
        }
    //Принт списка
    private static void printList(DLNode list) {
      if(list == null) {
        System.out.println("Your list is empty.");
      }else {
        while(list != null) {
          System.out.printf(list.data + "   ");
          list = list.next;
        }
      }
      System.out.println("");
    }
  //Просто создание узла
    private static DLNode createDLNode(int data) {
      DLNode newNode = new DLNode();
      newNode.data = data;
      newNode.next = null;
      newNode.prev = null;
      return newNode;

    }
    public static DLNode  deleteNotPrime(DLNode head) {
        if(head == null) {
          System.out.println("Error");
          return null;
        }
        DLNode pres = head;
        while(pres != null) {
          if(!Prime(pres.data)) {
            DLNode tmp = pres.next;
            head = remove(head, pres);
            pres = tmp;
          }
          else {
            pres = pres.next;
          }
        }
        return head;
      }
  //Удаление элемента
    public static DLNode remove(DLNode h, DLNode x) {
      if(h == null) return h;
      // check if x is the head
      if (x.prev != null) {
        x.prev.next = x.next;
      } else {
        h = h.next;
      }
      // check if x is the tail
      if (x.next != null) {
        x.next.prev = x.prev;
      }
      return h;
    }
  //ПРОСТЕ ЧИСЛО
    public static boolean Prime(int val) {
      if(val <= 1) return false;
          boolean isPrime = true;
          for(int i = 2; i <= Math.sqrt(val) && isPrime; i++) {
            if(val % i == 0) isPrime = false;
          }
          return isPrime;
        }
}