N,K = map(int,input().split())
MOD = 998244353
dp = [0]*(N+1)
dp[0] = 1
if N<2*K:
    for i in range(K,N+1):
        dp[i] = 1
elif N>=2*K:
    for i in range(K,2*K):
        dp[i] = 1
    cum = dp[K]
    for i in range(2*K,N+1):
        dp[i] = cum+1
        cum = (cum+dp[i-K+1])%MOD
ans = 0
for i in range(N+1):
    ans = (ans+dp[i])%MOD
print(ans)