(defconstant +mod+ 998244353)

(defun solve (n k)
  (let* ((dp (make-array (1+ n) :initial-element 0))
         (sum-dp (make-array (1+ n) :initial-element 0)))
    (setf (aref dp 0) 1)
    (setf (aref sum-dp 0) 1)

    (loop for i from 1 to n do
         (when (>= i k)
           (setf (aref dp i) (aref sum-dp (- i k))))
         (setf (aref sum-dp i) (mod (+ (aref sum-dp (1- i)) (aref dp i)) +mod+)))

    (let ((result 0))
      (loop for i from 0 to n do
           (setf result (mod (+ result (aref dp i)) +mod+)))
      result)))

(defun main ()
  (let ((n (read))
        (k (read)))
    (format t "~d~%" (solve n k))))

(main)