N, K = map(int, input().split())
INF = 10**18
MOD = 998244353

DP = [0] * (N + 2)
DP[0] = 1

for i in range(N + 1):

    DP[i] += DP[i - 1]
    DP[i] %= MOD

    if DP[i] == 0:
        continue
    # i+K に +DP[i] する
    if i + K <= N:
        DP[i + K] += DP[i]
        DP[i + K] %= MOD

    if i == 0:
        DP[i] = 0

DP[0] = 1
ans = 0
for i in range(0, N + 1):
    ans += DP[i]
    ans %= MOD
print(ans)