#include<bits/stdc++.h>
using namespace std;

#define all(a) a.begin(),a.end()
#define pb push_back
#define sz(a) ((int)a.size())

using ll=long long;
using u32=unsigned int;
using u64=unsigned long long;
using i128=__int128;
using u128=unsigned __int128;
using f128=__float128;

using pii=pair<int,int>;
using pll=pair<ll,ll>;

template<typename T> using vc=vector<T>;
template<typename T> using vvc=vc<vc<T>>;
template<typename T> using vvvc=vc<vvc<T>>;

using vi=vc<int>;
using vll=vc<ll>;
using vvi=vc<vi>;
using vvll=vc<vll>;

#define vv(type,name,n,...) \
    vector<vector<type>> name(n,vector<type>(__VA_ARGS__))
#define vvv(type,name,n,m,...) \
    vector<vector<vector<type>>> name(n,vector<vector<type>>(m,vector<type>(__VA_ARGS__)))

template<typename T> using min_heap=priority_queue<T,vector<T>,greater<T>>;
template<typename T> using max_heap=priority_queue<T>;

// https://trap.jp/post/1224/
#define rep1(n) for(ll i=0; i<(ll)(n); ++i)
#define rep2(i,n) for(ll i=0; i<(ll)(n); ++i)
#define rep3(i,a,b) for(ll i=(ll)(a); i<(ll)(b); ++i)
#define rep4(i,a,b,c) for(ll i=(ll)(a); i<(ll)(b); i+=(c))
#define cut4(a,b,c,d,e,...) e
#define rep(...) cut4(__VA_ARGS__,rep4,rep3,rep2,rep1)(__VA_ARGS__)
#define per1(n) for(ll i=((ll)n)-1; i>=0; --i)
#define per2(i,n) for(ll i=((ll)n)-1; i>=0; --i)
#define per3(i,a,b) for(ll i=((ll)a)-1; i>=(ll)(b); --i)
#define per4(i,a,b,c) for(ll i=((ll)a)-1; i>=(ll)(b); i-=(c))
#define per(...) cut4(__VA_ARGS__,per4,per3,per2,per1)(__VA_ARGS__)
#define rep_subset(i,s) for(ll i=(s); i>=0; i=(i==0?-1:(i-1)&(s)))

template<typename T, typename S> constexpr T ifloor(const T a, const S b){return a/b-(a%b&&(a^b)<0);}
template<typename T, typename S> constexpr T iceil(const T a, const S b){return ifloor(a+b-1,b);}

template<typename T>
void sort_unique(vector<T> &vec){
    sort(vec.begin(),vec.end());
    vec.resize(unique(vec.begin(),vec.end())-vec.begin());
}

template<typename T, typename S> constexpr bool chmin(T &a, const S b){if(a>b) return a=b,true; return false;}
template<typename T, typename S> constexpr bool chmax(T &a, const S b){if(a<b) return a=b,true; return false;}

template<typename T, typename S> istream& operator >> (istream& i, pair<T,S> &p){return i >> p.first >> p.second;}
template<typename T, typename S> ostream& operator << (ostream& o, const pair<T,S> &p){return o << p.first << ' ' << p.second;}

#ifdef i_am_noob
#define bug(...) cerr << "#" << __LINE__ << ' ' << #__VA_ARGS__ << "- ", _do(__VA_ARGS__)
template<typename T> void _do(vector<T> x){for(auto i: x) cerr << i << ' ';cerr << "\n";}
template<typename T> void _do(set<T> x){for(auto i: x) cerr << i << ' ';cerr << "\n";}
template<typename T> void _do(unordered_set<T> x){for(auto i: x) cerr << i << ' ';cerr << "\n";}
template<typename T> void _do(T && x) {cerr << x << endl;}
template<typename T, typename ...S> void _do(T && x, S&&...y) {cerr << x << ", "; _do(y...);}
#else
#define bug(...) 777771449
#endif

template<typename T> void print(vector<T> x){for(auto i: x) cout << i << ' ';cout << "\n";}
template<typename T> void print(set<T> x){for(auto i: x) cout << i << ' ';cout << "\n";}
template<typename T> void print(unordered_set<T> x){for(auto i: x) cout << i << ' ';cout << "\n";}
template<typename T> void print(T && x) {cout << x << "\n";}
template<typename T, typename... S> void print(T && x, S&&... y) {cout << x << ' ';print(y...);}

template<typename T> istream& operator >> (istream& i, vector<T> &vec){for(auto &x: vec) i >> x; return i;}

vvi read_graph(int n, int m, int base=1){
    vvi adj(n);
    for(int i=0,u,v; i<m; ++i){
        cin >> u >> v,u-=base,v-=base;
        adj[u].pb(v),adj[v].pb(u);
    }
    return adj;
}

vvi read_tree(int n, int base=1){return read_graph(n,n-1,base);}

template<typename T, typename S> pair<T,S> operator + (const pair<T,S> &a, const pair<T,S> &b){return {a.first+b.first,a.second+b.second};}

template<typename T> constexpr T inf=0;
template<> constexpr int inf<int> = 0x3f3f3f3f;
template<> constexpr ll inf<ll> = 0x3f3f3f3f3f3f3f3f;

template<typename T> vector<T> operator += (vector<T> &a, int val){for(auto &i: a) i+=val; return a;}

template<typename T> T isqrt(const T &x){T y=sqrt(x+2); while(y*y>x) y--; return y;}

#define ykh mt19937 rng(chrono::steady_clock::now().time_since_epoch().count())

#include<atcoder/all>
using namespace atcoder;

using mint=modint998244353;
//using mint=modint1000000007;

struct num{
    mint a,b;
    num(){a=b=0;}
    num(mint x){a=x,b=0;}
    num(mint x, mint y){a=x,b=y;}
    num operator + (num o){
        return {a+o.a,b+o.b};
    }
    num operator += (num o){
        return (*this)=(*this)+o;
    }
    num operator - (num o){
        return {a-o.a,b-o.b};
    }
    num operator * (num o){
        return {a*o.a+b*o.b*5,a*o.b+b*o.a};
    }
    num pow(ll m){
        num res(1);
        num cur=*this;
        for(; m; m>>=1,cur=cur*cur) if(m&1) res=res*cur;
        return res;
    }
};

template<typename T, int N>
struct matrix: array<array<T,N>,N>{
    matrix(){for(int i=0; i<N; ++i) for(int j=0; j<N; ++j) (*this)[i][j]=num(0);}
    void out(){
        for(int i=0; i<N; ++i){
            for(int j=0; j<N; ++j) cout << (*this)[i][j] << ' ';
            cout << "\n";
        }
    }
    void init(vector<T> vec){
        for(int i=0; i<N; ++i) for(int j=0; j<N; ++j) (*this)[i][j]=vec[i*N+j];
    }
    constexpr matrix id(){
        matrix res;
        for(int i=0; i<N; ++i) res[i][i]=num(1);
        return res;
    }
    matrix operator +(const matrix &mat2){
        matrix res;
        for(int i=0; i<N; ++i) for(int j=0; j<N; ++j) res[i][j]=(*this)[i][j]+mat2[i][j];
        return res;
    }
    matrix operator -(const matrix &mat2){
        matrix res;
        for(int i=0; i<N; ++i) for(int j=0; j<N; ++j) res[i][j]=(*this)[i][j]-mat2[i][j];
        return res;
    }
    matrix operator *(const matrix &mat2){
        matrix res;
        for(int i=0; i<N; ++i) for(int j=0; j<N; ++j) for(int k=0; k<N; ++k) res[i][j]+=(*this)[i][k]*mat2[k][j];
        return res;
    }
    matrix operator ^(ll x){
        assert(x>=0);
        matrix res=id(),cur=*this;
        for(; x; cur=cur*cur,x>>=1) if(x&1) res=res*cur;
        return res;
    }
};
template<typename T, int N>
ostream& operator << (ostream& o, matrix<T,N> x){
    for(int i=0; i<N; ++i){
        for(int j=0; j<N; ++j) o << x[i][j] << ' ';
        o << "\n";
    }
    return o;
}

template<typename T>
vector<vector<T>> calc_nCr(int n){
    vector<vector<T>> res;
    for(int i=0; i<n; ++i){
        res.pb(vector<T>(i+1));
        for(int j=0; j<=i; ++j){
            if(j==0||j==i) res[i][j]=1;
            else res[i][j]=res[i-1][j-1]+res[i-1][j];
        }
    }
    return res;
}

void ahcorz(){
    ll n; int k; cin >> n >> k;
    auto C=calc_nCr<mint>(k+2);
    num x(mint(2).inv(),mint(2).inv()),y(mint(2).inv(),-mint(2).inv());
    num res;
    rep(k+1){
        matrix<num,2> mat;
        mat[1][0]=mat[1][1]=num(1);
        mat[0][0]=x.pow(i)*y.pow(k-i);
        mat=mat^(n+1);
        res+=mat[1][0]*num(C[k][i])*num((k-i)&1?-1:1);
    }
    res=res*(num(0,mint(5).inv()).pow(k));
    print(res.a.val());
    //print(res.b.val());
}

signed main(){
    ios_base::sync_with_stdio(0),cin.tie(0);
    cout << fixed << setprecision(20);
    int t=1;
    //cin >> t;
    while(t--) ahcorz();
}