from sys import stdin
def input(): return stdin.readline()[:-1]

MOD = 998244353

class FenwickTree:
    def __init__(self, n) -> None:
        self.n = n
        self.bit = [0] * (n)
    
    def sum(self, r):
        ret = 0
        while r >= 0:
            ret += self.bit[r]
            ret %= MOD
            r = (r & (r + 1)) - 1
        return ret
    
    def add(self, idx, delta):
        while idx < self.n:
            self.bit[idx] += delta
            self.bit[idx] %= MOD
            idx |= idx + 1

def solve():
    n, k = map(int, input().split())
    tree = FenwickTree(n + 1)
    tree.add(0, 1)
    
    for i in range(1, n + 1):
        tree.add(i, tree.sum(i - k))
    print(tree.sum(n))
    
solve()