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