#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll mod = 998244353;
const int N = 200005;
const int INF = 0x3f3f3f3f;
int solve(int n, int k) {
    vector<int> f(k + 1, 0), g(k + 1, 0);
    f[0] = 1;
    int tot = 2 * n;
    for (int s = 0; s < tot; s++) {
        fill(g.begin(), g.end(), 0);
        for (int h = 0; h <= k; h++) {
            int v = f[h];
            if (!v) continue;
            if (h + 1 <= k) g[h + 1] = (g[h + 1] + v) % mod;
            if (h > 0) g[h - 1] = (g[h - 1] + v) % mod;
        }
        f.swap(g);
    }
    return f[0];
}
int main() {
    int n, k;
    cin >> n >> k;
    int tot = solve(n, k);
    int tot2 = (k >= 1 ? solve(n, k - 1) : 0);
    int ans = tot - tot2;
    if (ans < 0) ans += mod;
    cout << ans << "\n";
    return 0;
}