MOD = 998244353
N, K = map(int, input().split())
dp = [0] * (N + 1)
cs = [0] * (N + 1)
dp[0] = 1
cs[0] = 1

for i in range(1, N + 1):
    if i - K >= 0:
        dp[i] = cs[i - K]
    cs[i] = (cs[i - 1] + dp[i]) % MOD

print(cs[-1])