#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <iostream>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <queue>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <random>
#include <stdio.h>
#include <fstream>
#include <functional>
#include <cassert>
#include <atcoder/modint>


using namespace std;
using namespace atcoder;

using mint  = modint998244353;


#define rep(i,n) for (int i=0;i<n;i+=1)
#define append push_back
#define all(x) (x).begin(), (x).end()

template<class T>
using vec = vector<T>;
template<class T>
using vvec = vec<vec<T>>;
template<class T>
using vvvec = vec<vvec<T>>;
using ll = long long;
using pii = pair<int,int>;
using pll = pair<ll,ll>;


template<class T>
bool chmin(T &a, T b){
  if (a>b){
    a = b;
    return true;
  }
  return false;
}

template<class T>
bool chmax(T &a, T b){
  if (a<b){
    a = b;
    return true;
  }
  return false;
}

template<class T>
T sum(vec<T> x){
  T res=0;
  for (auto e:x){
    res += e;
  }
  return res;
}

template<class T>
void printv(vec<T> x){
  for (auto e:x){
    cout<<e<<" ";
  }
  cout<<"\n";
}

template<class T>
ostream& operator<<(ostream& os, const vec<T>& A){
  os << "{";
  rep(i,A.size()){
    os << A[i];
    if (i!=A.size()-1){
      os << ", ";
    }
  }
  os << "}" ;
  return os;
}

template<class T>
ostream& operator<<(ostream& os, const deque<T>& A){
  os << "deque{[";
  rep(i,A.size()){
    os << A[i];
    if (i!=A.size()-1){
      os << ", ";
    }
  }
  os << "]}" ;
  return os;
}

template<class T>
ostream& operator<<(ostream& os, const pair<T,T>& A){
  os << "(";
  os << A.first ;
  os << ", ";
  os << A.second;
  os << ")";
  return os;
}

pair<mint,mint> omega_prod(pair<mint,mint> X,pair<mint,mint> Y){
  auto [a,b] = X;
  auto [c,d] = Y;
  return {(a*d+b*c-a*c),b*d-a*c};
};

pair<mint,mint> omega_pow(pair<mint,mint> X,int N){
  pair<mint,mint> res = {0,1};
  while (N){
    if ((N&1)){
      res = omega_prod(res,X);
    }
    X = omega_prod(X,X);
    N >>= 1;
  }
  return res;
}

ostream& operator<<(ostream& os, const mint a){
  os << a.val();
  return os;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int N,M;
    cin>>N>>M;


    vec<vec<pair<mint,mint>>> dp(2*M+1,vec<pair<mint,mint>>(2*M+1,{0,0}));
    pair<mint,mint> zero = {0,0};
    dp[M][M] = {0,1};
    mint i3 = mint(3).inv();
    for (int _=0;_<M;_++){
      vec<vec<pair<mint,mint>>> ndp(2*M+1,vec<pair<mint,mint>>(2*M+1,{0,0}));
      for (int i=0;i<=2*M;i++){
        for (int j=0;j<=2*M;j++){
          if (dp[i][j] == zero) continue;
          auto e = dp[i][j];
          ndp[i][j+1].first += e.first * i3;
          ndp[i][j+1].second += e.second * i3;

          e = omega_prod(e,{1,0});
          ndp[i-1][j-1].first += e.first * i3;
          ndp[i-1][j-1].second += e.second * i3;

          e = omega_prod(e,{1,0});
          ndp[i+1][j].first += e.first * i3;
          ndp[i+1][j].second += e.second * i3;
        }
      }
      swap(dp,ndp);
    }

    mint res = 0;
    for (int i=0;i<=2*M;i++){
      for (int j=0;j<=2*M;j++){
        auto e = omega_pow({i-M,j-M},N);
        auto f = omega_prod(dp[i][j],e);
        res += f.second;
      }
    }

    cout << res.val() << endl;

    

    

    

}