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

// #define int long long
#define ls (p<<1)
#define rs (p<<1|1)
#define mid ((l+r)>>1)
#define all(_array) (_array).begin(),(_array).end()
#define msp(_array) memset(_array,0x3f,sizeof _array)
#define ms0(_array) memset(_array,0,sizeof _array)
#define msn(_array) memset(_array,-1,sizeof _array)
#define mc(_tar,_array) memcpy(_tar,_array,sizeof _tar)
#define Yes cout<<"Yes"<<endl
#define No cout<<"No"<<endl
#define YES cout<<"YES"<<endl
#define NO cout<<"NO"<<endl
#define TAK cout<<"TAK"<<endl
#define NIE cout<<"NIE"<<endl
#define OK cerr<<"OK"<<endl
#define pii pair<int,int>
#define endl '\n'

bool bg_memory;
mt19937 rnd(time(0));
int Case=1;
const int mod=998244353;
const int inf=2147483647;
const int bs=233;
const double eps=1e-6;
const int N=1e5+7,M=1e5+7;

template<class _t1,class _t2>inline void cmax(_t1 &a,_t2 b){a=a<b?b:a;}
template<class _t1,class _t2>inline void cmin(_t1 &a,_t2 b){a=a>b?b:a;}

inline int sqrt(int x,int r){int l=0,ans=0;while(l<=r){if(1ll*mid*mid<=x) ans=mid,l=mid+1;else r=mid-1;}return ans;}

int n,m;
struct mtx{
    int a[4][4];
    int*operator[](int x){return a[x];}
    mtx(int x=0){ms0(a);if(x)for(int i=1;i<=3;i++)a[i][i]=1;}
}g;
int pla;
// int dp[N][4];
// void solve(int a){
//     dp[2][a]=1;
//     for(int i=3;i<=n+2;i++){
//         dp[i][1]=dp[i-1][2];
//         dp[i][2]=dp[i-1][1]+dp[i-1][3];
//         dp[i][3]=dp[i-1][1];
//     }
// }
mtx operator*(mtx a,mtx b){
    mtx ans=0;
    for(int i=1;i<=3;i++){
        for(int j=1;j<=3;j++){
            for(int k=1;k<=3;k++){
                (ans[i][j]+=1ll*a[i][k]*b[k][j]%mod)%=mod;
            }
        }
    }
    return ans;
}
unordered_map<int,int> ump;
inline mtx qp(mtx a,int b,int p=mod){mtx res=1;while(b){if(b&1)res=res*a;a=a*a;b>>=1;}return res;}
inline int solve(int m){
    if(ump.count(m)) return ump[m];
    if(m==0) return ump[m]=1;
    if(m&1) return ump[m]=1ll*solve(m>>1)*pla%mod;
    return ump[m]=(solve(m>>1)+solve((m>>1)-1))%mod;
}

void Main(){
    
    cin>>n>>m;
    g[2][1]=g[1][2]=g[3][2]=g[1][3]=1;
    g=qp(g,n);
    for(int i=1;i<=3;i++) (pla+=g[i][i])%=mod;
    cout<<solve(m)<<endl;

    return;
}
string RdFile="";
bool en_memory;

signed main(){
    auto bg_clock=chrono::high_resolution_clock::now();
#ifdef ONLINE_JUDGE
    // freopen((RdFile+".in").c_str(),"r",stdin);
    // freopen((RdFile+".out").c_str(),"w",stdout);
#endif
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    // cin>>Case;
    while(Case--) Main();
    auto en_clock=chrono::high_resolution_clock::now();
    auto duration_clock=chrono::duration_cast<chrono::microseconds>(en_clock-bg_clock);
    double duration_count=duration_clock.count()*0.001;
    double memory_used=(&en_memory-&bg_memory)/1024.0/1024;
    // cerr<<"Time:"<<duration_count<<"ms"<<endl;
    // cerr<<"Memory: "<<memory_used<<"MB"<<endl;
    return 0;
}