Index(Node<K,V> node,Index<K,V> down,Index<K,V> right){
  this.node=node;
  this.down=down;
  this.right=right;
}

Index ( Node < K , V > node , Index < K , V > down , Index < K , V > right ) { this . node = node ; this . down = down ; this . right = right ; }
creates index node with given values .
