#include<bits/stdc++.h>
namespace {
#pragma GCC diagnostic ignored "-Wunused-function"
#include<atcoder/all>
#pragma GCC diagnostic warning "-Wunused-function"
using namespace std;
using namespace atcoder;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define rrep(i,n) for(int i = (int)(n) - 1; i >= 0; i--)
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
template<class T> bool chmax(T& a, const T& b) { if (a < b) { a = b; return true; } else return false; }
template<class T> bool chmin(T& a, const T& b) { if (b < a) { a = b; return true; } else return false; }
using ll = long long;
using P = pair<int,int>;
using VI = vector<int>;
using VVI = vector<VI>;
using VL = vector<ll>;
using VVL = vector<VL>;
using mint = modint998244353;

} int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, k;
  cin >> n >> k;
  auto f = [&](int k) -> mint {
    vector<mint> dp(k), ndp;
    dp[0] = 1;
    rep(_, 2 * n) {
      ndp.assign(k, 0);
      rep(i, k) {
        if (i) ndp[i-1] += dp[i];
        if (i+1 < k) ndp[i+1] += dp[i];
      }
      swap(dp, ndp);
    }
    return dp[0];
  };
  mint ans = f(k+1) - f(k);
  cout << ans.val() << '\n';
}