#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define mkp make_pair
#define pir pair <ll, ll>
#define pb emplace_back
#define i128 __int128
using namespace std;
template <class T>
void rd(T &x) {
	char ch; ll f = 0;
	while(!isdigit(ch = getchar()))
		if(ch == '-') f = 1;
	x = ch - '0';
	while(isdigit(ch = getchar()))
		x = (x << 1) + (x << 3) + ch - '0';
	if(f) x = -x;
}
const ll maxn = 510, mod = 998244353;
template <class T>
void add(T &x, const T y) { x = x + y >= mod? x + y - mod : x + y; }
ll n, m, f[33][2], val;
struct mat {
	ll dat[3][3];
	const mat operator * (const mat &t) {
		mat ret; memset(ret.dat, 0, sizeof ret.dat);
		for(ll i = 0; i < 3; i++)
			for(ll j = 0; j < 3; j++)
				for(ll k = 0; k < 3; k++)
					ret.dat[i][j] = (ret.dat[i][j]
					 + dat[i][k] * t.dat[k][j]) %mod;
		return ret;
	}
} base, ret;
void getval() {
	ll k = n - 1;
	base.dat[0][1] = base.dat[1][2] = 1;
	base.dat[1][0] = base.dat[2][0] = 1;
	ret.dat[0][0] = ret.dat[1][1] = ret.dat[2][2] = 1;
	while(k) {
		if(k & 1) ret = ret * base;
		base = base * base, k >>= 1;
	}
	val = (ret.dat[0][1] * 2
	 + ret.dat[0][2] * 3 + (n < 3? 1 : 0)) %mod;
}
int main() {
	rd(n), rd(m), f[0][0] = 1;
	getval();
	for(ll i = 1; i <= 30; i++) {
		ll c = (m >> i - 1) & 1;
		if(c) {
			add(f[i][0], f[i - 1][0] * val %mod);
			add(f[i][0], f[i - 1][1]);
			add(f[i][1], f[i - 1][1]);
		} else {
			add(f[i][0], f[i - 1][0]);
			add(f[i][1], f[i - 1][0]);
			add(f[i][1], f[i - 1][1] * val %mod);
		}
	} printf("%lld", f[30][0]);
	return 0;
}