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])