(defconstant +mod+ 998244353)

(defun main (&rest argv)
  (declare (ignorable argv))
  (let* ((n (read))
         (k (read))
         (dp1 (make-array (1+ n) :initial-element 0))
         (dp2 (make-array (1+ n) :initial-element 0)))
    (setf (aref dp1 0) 1)
    (setf (aref dp2 0) 1)
    (loop for i from 1 to n
          if (minusp (- i k))
            do (setf (aref dp1 i) 0)
          else
            do (incf (aref dp1 i) (aref dp2 (- i k)))
               (setf (aref dp1 i) (mod (aref dp1 i) +mod+))
          do (incf (aref dp2 i) (+ (aref dp2 (1- i)) (aref dp1 i)))
             (setf (aref dp2 i) (mod (aref dp2 i) +mod+)))
    (format t "~d~%" (aref dp2 n))))

(main)