#include <bits/stdc++.h>
char buf[5000000], *p1, *p2;
#define nc() (p1==p2&&(p2=(p1=buf)+fread(buf,1,5000000,stdin),p1==p2)?EOF:*p1++)
template<typename T>
inline void read_s(T& x) {x=0;bool f=0;int ch;while(!isdigit(ch=nc()))f|=ch=='-';do{x=x*10+(ch^48);}while(isdigit(ch=nc()));f&&(x=-x);}
template<typename... Args>
void read(Args& ...args) {
  (read_s(args), ...);
}
#define mod 998244353ll
using ll = long long;
void add(ll& x, ll y) {
  x += y - mod;
  x += (x >> 63) & mod;
}
struct matrix {
  ll a[3][3];
  ll* operator[] (int x) {return a[x];}
  const ll* operator[] (int x) const {return a[x];}
  static matrix geti() {
    matrix res{};
    for (int i = 0; i < 3; ++i) res[i][i] = 1;
    return res;
  }
  matrix operator* (const matrix& b) const {
    matrix res{};
    for (int i = 0; i < 3; ++i) {
      for (int k = 0; k < 3; ++k) {
        for (int j = 0; j < 3; ++j) {
          add(res[i][j], a[i][k] * b[k][j] % mod);
        }
      }
    }
    return res;
  }
};
matrix qp(matrix a, ll y) {
  matrix res = matrix::geti();
  while (y) {
    if (y & 1) res = res * a;
    a = a * a;
    y >>= 1;
  }
  return res;
}
ll w(int n) {
  matrix base{
    0, 1, 1,
    1, 0, 0,
    0, 1, 0,
  };
  auto res = qp(base, n - 3);
  ll ans = (3 * res[0][0] + 2 * res[0][1]) % mod;
  return ans;
}
int n, m;
ll f[31][2];
int main() {
  std::cin.tie(nullptr) -> sync_with_stdio(false);
  read(n, m);
  ll v = w(n);
  f[0][0] = 1;
  for (int i = 1; i <= 30; ++i) {
    if ((m >> (i - 1)) & 1) {
      f[i][0] = f[i - 1][1];
      add(f[i][0], f[i - 1][0] * v % mod);
      f[i][1] = f[i - 1][1];
    } else {
      f[i][0] = f[i - 1][0];
      f[i][1] = f[i - 1][0];
      add(f[i][1], f[i - 1][1] * v % mod);
    }
  }
  std::cout << f[30][0] << '\n';
  return 0;
}