#include <bits/stdc++.h>
using namespace std;
using ll = long long;

template<long long MOD>
struct modint {
public:
	modint (long long _v = 0) : v(_v % MOD) { if (v < 0) v += MOD; }
	
	long long val() const { return v; }
	modint operator - () const { return modint(-v); }
	modint operator + (const modint &r) { return modint(*this) += r; }
	modint operator - (const modint &r) { return modint(*this) -= r; }
	modint operator * (const modint &r) { return modint(*this) *= r; }
	modint operator / (const modint &r) { return modint(*this) /= r; }
	modint &operator += (const modint &r) {
		if ((v += r.v) >= MOD) v -= MOD;
		return *this;
	}
	modint &operator -= (const modint &r) {
		if ((v += MOD - r.v) >= MOD) v -= MOD;
		return *this;
	}
	modint &operator *= (const modint &r) {
		v = v * r.v % MOD;
		return *this;
	}
	modint &operator /= (const modint &r) {
		v = v * r.inv() % MOD;
		return *this;
	}
	
	modint inv() const {
		long long a = v, b = MOD, p = 1, q = 0;
		while (b) {
			long long t = a / b;
			a -= t * b; swap(a, b);
			p -= t * q; swap(p, q);
		}
		p %= MOD;
		if (p < 0) p += MOD;
		return p;
	}
	
	modint pow(long long n) const {
		assert(0 <= n);
		modint x = *this, res = 1;
		while (n) {
			if (n & 1) res *= x;
			x *= x;
			n >>= 1;
		}
		return res;
	}
	
private:
	long long v;
};

using mint = modint<998244353>;

int main() {
	cin.tie(nullptr);
	ios_base::sync_with_stdio(false);
	
	int N, K;
	cin >> N >> K;
	vector<mint> dp(N + 1);
	dp[0] = 1;
	for (int i = 1; i <= N; i++) {
		dp[i] = dp[i - 1];
		if (i < K) continue;
		dp[i] += dp[i - K];
	}
	cout << dp[N].val() << '\n';
}