MOD=998244353

n,k=map(int,input().split())

dp=[0]*(n+1)
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
    
print(dp[n]%MOD)