#include #include using namespace std; using namespace atcoder; //using mint = modint1000000007; //const int mod = 1000000007; using mint = modint998244353; const int mod = 998244353; //const int INF = 1e9; //const long long LINF = 1e18; #define rep(i, n) for (int i = 0; i < (n); ++i) #define rep2(i,l,r)for(int i=(l);i<(r);++i) #define rrep(i, n) for (int i = (n) - 1; i >= 0; --i) #define rrep2(i,l,r)for(int i=(r) - 1;i>=(l);--i) #define all(x) (x).begin(),(x).end() #define allR(x) (x).rbegin(),(x).rend() #define P pair template inline bool chmax(A & a, const B & b) { if (a < b) { a = b; return true; } return false; } template inline bool chmin(A & a, const B & b) { if (a > b) { a = b; return true; } return false; } int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n, k; cin >> n >> k; vector dp(5, vector()); dp[0] = {1}; auto add = [&](vector& dp, vector& ndp, int add) { if (dp.size() + add > ndp.size()) ndp.resize(dp.size() + add); rep(i, dp.size()) ndp[i + add] += dp[i]; }; rep(i, n - 1) { vector ndp(5, vector()); swap(dp[0], dp[2]); swap(dp[3], dp[4]); rep(i, 3)rep(j, 3)add(dp[i], ndp[j], j != 0); add(dp[0], ndp[3], 2); add(dp[2], ndp[4], 2); add(dp[3], ndp[2], 1); add(dp[3], ndp[3], 2); add(dp[4], ndp[0], 0); add(dp[4], ndp[4], 2); swap(dp, ndp); } mint ans = 0; rep(i, 4)rep(j, k + 1)if (j < dp[i].size())ans += dp[i][j]; cout << ans.val() << endl; return 0; }