#include <iostream>
#include <vector>

#define  MOD   998244353

using namespace std;

int main()
{
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int N, K, i;
    cin >> N >> K;
    vector<int> dp(N + 1, 0), sum(N + 1, 1);
    dp[0] = 1, sum[0] = 1;

    for (i = K; i <= N; ++i)
        dp[i] = sum[i - K], sum[i] = (sum[i - 1] + dp[i]) % MOD;

    cout << sum[N] << '\n';
    return 0;
}