#include <bits/stdc++.h>
#define all(x) x.begin(), x.end()
#define pb push_back
#define eb emplace_back
#define rz resize
#define Siz(a) (int)(a.size())
#define MP make_pair
#define MT make_tuple
#define IT iterator
#define fi first
#define se second
#define For(i, a, b) for (int i = (int)(a); i <= (int)(b); ++i)
#define Rep(i, a, b) for (int i = (int)(a); i >= (int)(b); --i)
#define CLR(a, v) memset(a, v, sizeof(a))
#define CPY(a, b) memcpy(a, b, sizeof(a))
#define debug cerr << "ztxakking\n"
#define y0 ztxaknoi
#define y1 ztxakioi
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
using uint = unsigned int;
using i128 = __int128_t;
using u128 = __uint128_t;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pli = pair<ll, int>;
using pil = pair<int, ll>;
using vi = vector<int>;
template<typename T>
using V = vector<T>;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
template<const int MOD>
struct Modular {
  int val;
  Modular(int x = 0) : val(x) {}
  friend Modular operator + (Modular x, Modular y) { int res = x.val + y.val; if (res >= MOD) res -= MOD; return res; }
  friend Modular operator - (Modular x, Modular y) { int res = x.val - y.val; if (res < 0) res += MOD; return res; }
  friend Modular operator * (Modular x, Modular y) { int res = 1ll * x.val * y.val % MOD; return res; }
  Modular &operator += (Modular x) { *this = *this + x; return *this; }
  Modular &operator -= (Modular x) { *this = *this - x; return *this; }
  Modular &operator *= (Modular x) { *this = *this * x; return *this; }
  Modular &operator ++ () { *this = *this + 1; return *this; }
  Modular &operator ++ (int) { *this = *this + 1; return *this; }
  Modular &operator -- () { *this = *this - 1; return *this; }
  Modular &operator -- (int) { *this = *this - 1; return *this; }
  Modular operator - () { int res = val; if (res) res = MOD - res; return res; }
  static Modular pow(Modular x, ll p) {
    Modular ans(1);
    for (; p; p /= 2, x *= x) {
      if (p & 1) ans *= x;
    }
    return ans;
  }
  static Modular inv(Modular x) { return pow(x, MOD - 2); }
  friend Modular operator / (Modular x, Modular y) { return x * inv(y); }
  Modular &operator /= (Modular x) { *this = *this / x; return *this; }
  friend bool operator == (Modular x, Modular y) { return x.val == y.val; }
  friend bool operator != (Modular x, Modular y) { return x.val != y.val; }
  friend bool operator < (Modular x, Modular y) { return x.val < y.val; }
  friend bool operator > (Modular x, Modular y) { return x.val > y.val; }
  friend bool operator <= (Modular x, Modular y) { return x.val <= y.val; }
  friend bool operator >= (Modular x, Modular y) { return x.val >= y.val; }
  friend istream &operator >> (istream &in, Modular &item) { in >> item.val; return in; }
  friend ostream &operator << (ostream &out, Modular item) { out << item.val; return out; }
};
using mint = Modular<998244353>;
int n, m;
mint w[3], f[31][4];
struct Matrix {
  int n, m;
  mint a[3][3];
  Matrix() {
    n = m = 0;
    For(i, 0, 2) For(j, 0, 2) a[i][j] = 0;
  }
  friend Matrix operator * (Matrix A, Matrix B) {
    Matrix C; C.n = A.n, C.m = B.m;
    For(i, 0, C.n - 1) For(k, 0, A.m - 1) For(j, 0, C.m - 1) {
      C.a[i][j] += A.a[i][k] * B.a[k][j];
    }
    return C;
  }
} X, T;
Matrix qpow(Matrix X, Matrix T, int p) {
  while (p) {
    if (p & 1) X = T * X;
    T = T * T, p >>= 1;
  }
  return X;
}
void Main() {
  cin >> n >> m;
  w[0] = w[2] = 1;
  T.n = T.m = 3;
  T.a[1][0] = T.a[2][0] = T.a[2][1] = T.a[0][2] = 1;
  X.n = 3, X.m = 1;
  X.a[0][0] = X.a[1][0] = X.a[2][0] = 0, X.a[0][0] = 1;
  X = qpow(X, T, n - 2);
  w[1] += X.a[0][0] + X.a[1][0];
  X.a[0][0] = X.a[1][0] = X.a[2][0] = 0, X.a[1][0] = 1;
  X = qpow(X, T, n - 2);
  w[1] += X.a[2][0];
  X.a[0][0] = X.a[1][0] = X.a[2][0] = 0, X.a[2][0] = 1;
  X = qpow(X, T, n - 2);
  w[1] += X.a[0][0] + X.a[2][0];
  f[30][0] = 1;
  Rep(i, 29, 0) For(j, 0, 3) {
    int t = j << 1;
    if (m >> i & 1) ++t;
    For(k, 0, 2) {
      if (t - k >= 0 && t - k <= 3) {
        f[i][t - k] += f[i + 1][j] * w[k];
      }
    }
  }
  cout << f[0][0] << '\n';
}
int main() {
  #ifndef ONLINE_JUDGE
  freopen("C.in", "r", stdin) && freopen("C.out", "w", stdout);
  #endif
  ios::sync_with_stdio(0), cin.tie(0);
  int t = 1;
  // cin >> t;
  while (t--) Main();
  cerr << (double)(clock()) / CLOCKS_PER_SEC << '\n';
  return 0;
}