import sys
input = sys.stdin.readline
MOD = 998244353
N, K = map(int, input().split())
dp = [0 for _ in range(N+1)]
if K<=N:
    dp[K] = 1
else:
    print(1)
    exit()
s = 0
for i in range(N+1):
    s += dp[i]
    if s==0:
        continue
    if i+K<=N:
        dp[i+K] += s
        dp[i+K] %= MOD
#print(dp)
ans = 1
s = 0
for i in range(N+1):
    s += dp[i]
    s %= MOD
    ans += s
    ans %= MOD
print(ans)