#include <bits/stdc++.h>

const int mod = 998244353;

struct Mat {
  int a[3][3];
  Mat() { memset(a, 0, sizeof(a)); }
  Mat operator * (const Mat &t) const {
    Mat ans;
    for (int i : {0, 1, 2}) for (int j : {0, 1, 2}) for (int k : {0, 1, 2})
      (ans.a[i][j] += 1ll * a[i][k] * t.a[k][j] % mod) %= mod;
    return ans;
  }
};

int main() {
  int n, m; scanf("%d %d", &n, &m);
  Mat s, t;
  for (int i = 0; i < 3; i++) s.a[i][i] = 1;
  t.a[0][1] = t.a[0][2] = t.a[1][0] = t.a[2][1] = 1;
  for (int k = n - 2; k; k >>= 1) {
    if (k & 1) s = s * t;
    t = t * t;
  }
  int res = ((long long) s.a[0][0] + s.a[0][2] + s.a[1][0] + s.a[1][1] + s.a[2][1]) % mod;
  // printf("%d\n", res);
  std::vector<std::vector<int>> f(31, std::vector<int>(2));
  if (m & 1) f[0][0] = res;
  else f[0][0] = f[0][1] = 1;
  for (int i = 1; i <= 30; i++) {
    if (m & (1 << i)) {
      f[i][0] = (1ll * res * f[i - 1][0] % mod + f[i - 1][1]) % mod;
      f[i][1] = f[i - 1][1];
    } else {
      f[i][0] = f[i - 1][0];
      f[i][1] = (1ll * res * f[i - 1][1] + f[i - 1][0]) % mod;
    }
  }
  printf("%d\n", f[30][0]);
}