#include using namespace std; typedef long long ll; typedef pair pii; #define pb push_back #define all(a) a.begin(), a.end() #define sz(a) ((int)a.size()) #ifdef Doludu template ostream& operator << (ostream &o, vector vec) { o << "{"; int f = 0; for (T i : vec) o << (f++ ? " " : "") << i; return o << "}"; } void bug__(int c, auto ...a) { cerr << "\e[1;" << c << "m"; (..., (cerr << a << " ")); cerr << "\e[0m" << endl; } #define bug_(c, x...) bug__(c, __LINE__, "[" + string(#x) + "]", x) #define bug(x...) bug_(32, x) #define bugv(x...) bug_(36, vector(x)) #define safe bug_(33, "safe") #else #define bug(x...) void(0) #define bugv(x...) void(0) #define safe void(0) #endif const int mod = 998244353, N = 2000006; struct mat { int n; long long mod2; vector > val; mat () = default; mat (int _n, int _mode = 0) : n(_n), mod2(1ll * mod * mod) { // mode 1 -> I, other -> O val.assign(n, vector(n, 0)); if (_mode == 1) { for (int i = 0; i < n; ++i) val[i][i] = 1; } } mat (const mat& M) : n(M.n), mod2(1ll * mod * mod) { val.assign(n, vector(n, 0)); for (int i = 0; i < n; ++i) { for (int j = 0; j < n; ++j) { val[i][j] = M.val[i][j]; } } } mat (vector > v) : n(v.size()), mod2(1ll * mod * mod), val(v) {} mat operator + (const mat& o) { mat ans(o); for (int i = 0; i < n; ++i) { for (int j = 0; j < n; ++j) { ans.val[i][j] += val[i][j]; if (ans.val[i][j] >= mod) ans.val[i][j] -= mod; } } return ans; } mat operator * (const mat& o) { mat ans(n, 0); for (int i = 0; i < n; ++i) { for (int k = 0; k < n; ++k) { for (int j = 0; j < n; ++j) { ans.val[i][j] += val[i][k] * o.val[k][j]; if (ans.val[i][j] >= mod2) ans.val[i][j] -= mod2; } } } for (int i = 0; i < n; ++i) { for (int j = 0; j < n; ++j) { ans.val[i][j] %= mod; } } return ans; } mat operator ^ (long long k) { mat ans(n, 1), a(*this); for (; k; k >>= 1, a = a * a) { if (k & 1) ans = ans * a; } return ans; } mat& operator = (mat o) { this->n = o.n, this->val = o.val, this->mod2 = o.mod2; return *this; } }; int add(int a, int b) { a += b; if (a >= mod) a -= mod; return a; } int sub(int a, int b) { a -= b; if (a < 0) a += mod; return a; } int mul(int a, int b) { return 1ll * a * b % mod; } int Pow(int a, int b) { int ans = 1; for (; b; b >>= 1, a = mul(a, a)) if (b & 1) ans = mul(ans, a); return ans; } int main() { ios::sync_with_stdio(false), cin.tie(0); int n; ll k; cin >> n >> k; vector a(4 * n + 1, vector(4 * n + 1, 0ll)); int inv = Pow(5, mod - 2); for (int i = 0; i < 4 * n; ++i) { a[i][i + 1] = inv; if ((i & 3) != 0) a[i][1] = inv, a[i][0] = mul(3, inv); else a[i][0] = mul(4, inv); } mat M(a); M = M ^ k; cout << M.val[0][4 * n] << "\n"; }