#include <bits/stdc++.h>
#define _for(i, a, b) for (int i = a; i <= b; ++i)
#define for_(i, a, b) for (int i = a; i >= b; --i)
#define far(i, vec) for (auto i : vec)
#define bdmd int mid = (l + r) >> 1
typedef long double ldb;
typedef long long ll;
typedef double db;
typedef std::pair <int, int> pii;
typedef std::pair <ll, ll> pll;
const int N = 1e5 + 10, P = 998244353;
namespace IO {
	int rnt () {
		int x = 0, w = 1; char c = getchar ();
		while (!isdigit (c)) { if (c == '-') w = -1; c = getchar (); }
		while (isdigit (c)) x = (x << 3) + (x << 1) + (c ^ 48), c = getchar ();
		return x * w;
	}
}
namespace MATRIX {
	template <const int N, const int M, typename T = int, class C1 = std::plus <T>, class C2 = std::multiplies <T> >
	class Matrix {
	private:
		std::array <std::array <T, M>, N> a;

	public:
		Matrix (T val = 0) { far (&b, a) b.fill (val); }
		Matrix (std::array <std::array <T, M>, N> a) : a (a) {}
		std::array <T, M>& operator [] (int i) { return a[i]; }
		void Print (int n = N, int m = M) {
			_for (i, 0, n - 1) {
				_for (j, 0, m - 1)
					printf ("%d ", a[i][j]);
				puts ("");
			}
			puts ("");
			return;
		}
	};
	template <const int N, const int K, const int M, typename T = int, class C1 = std::plus <T>, class C2 = std::multiplies <T>>
	Matrix <N, M, T, C1, C2> operator * (Matrix <N, K, T, C1, C2> A, Matrix <K, M, T, C1, C2> B) {
		Matrix <N, M, T, C1, C2> C;
		_for (i, 0, N - 1) _for (k, 0, K - 1) _for (j, 0, M - 1)
			C[i][j] = C1 () (C[i][j], C2 () (A[i][k], B[k][j]));
		return C;
	}
	template <const int N, typename T, typename C1, typename C2>
	void IMat (Matrix <N, N, T, C1, C2>& I) {
		_for (i, 0, N - 1) {
			_for (j, 0, N - 1)
				I[i][j] = 0;
			I[i][i] = 1;
		}
		return;
	}
	template <const int N, typename T = int, class C1 = std::plus <T>, class C2 = std::multiplies <T>, typename KT>
	Matrix <N, N, T, C1, C2> operator ^ (Matrix <N, N, T, C1, C2> a, KT K) {
		Matrix <N, N, T, C1, C2> ans; IMat (ans);
		for (; K; a = a * a, K >>= 1)
			if (K & 1) ans = ans * a;
		return ans;
	}
    template <typename T> class PlusMod { public: T operator () (T a, T b) { return (a + b) % P; }};
	template <typename T> class MultMod { public: T operator () (T a, T b) { return 1ll * a * b % P; }};
}
namespace SOLVE {
	using namespace IO;
	using namespace MATRIX;
	typedef Matrix <3, 3, int, PlusMod <int>, MultMod <int> > Mat4;
	int n, m, F[31][2], ans;
	void In () {
		n = rnt (), m = rnt ();
		return;
	}
	void Solve () {
		Mat4 A (0);
		A[0][1] = 1, A[1][0] = 1;
		A[0][2] = 1, A[2][1] = 1;
		A = A ^ n;
		int S = (0ll + A[0][0] + A[1][1] + A[2][2]) % P;
		if (m & 1) F[0][0] = S, F[0][1] = 0;
		else F[0][0] = F[0][1] = 1;
		_for (b, 1, 30) {
			int k = (m >> b) & 1;
			F[b][k] = F[b - 1][k];
			F[b][k ^ 1] = (F[b - 1][k] + 1ll * F[b - 1][k ^ 1] * S) % P;
		}
		return;
	}
	void Out () {
		printf ("%d\n", F[30][0]);
		return;
	}
}
int main () {
	SOLVE::In ();
	SOLVE::Solve ();
	SOLVE::Out ();
	return 0;
} /*

*/