#include<bits/stdc++.h>
using namespace std;
template<class T1,class T2> bool cmax(T1& a,const T2& b){return a<b?a=b,1:0;}
template<class T1,class T2> bool cmin(T1& a,const T2& b){return b<a?a=b,1:0;}
#define fir(i,x,y,...) for(int i(x),##__VA_ARGS__;i<=(y);i++)
#define firr(i,x,y,...) for(int i(x),##__VA_ARGS__;i>=(y);i--)
#define fird(i,x,y,d,...) for(int i(x),##__VA_ARGS__;i<=(y);i+=(d))
#define firrd(i,x,y,d,...) for(int i(x),##__VA_ARGS__;i>=(y);i-=(d))
#define Yes cout<<"Yes\n"
#define No cout<<"No\n"
#define YES cout<<"YES\n"
#define NO cout<<"NO\n"
#define endl "\n"
#define ll long long
#define ull unsigned long long
int T;
bool _mul=0;
int gcd(int x,int y){if(!y) return x;return gcd(y,x%y);}
int power(int b,int p,int mod){int res=1;while(p){if(p&1) res=1ll*res*b%mod;b=1ll*b*b%mod;p>>=1;}return res;}
const int mod=998244353;
int n,m,x;
struct mat
{
    int a[3][3];
    mat operator*(const mat &x)
    {
        mat res{};
        fir(i,0,2) fir(k,0,2) fir(j,0,2) (res.a[i][j]+=1ll*a[i][k]*x.a[k][j]%mod)%=mod;
        return res;
    }
    mat operator^(int p)
    {
        mat res{};
        mat base{};
        fir(i,0,2) res.a[i][i]=1;
        fir(i,0,2) fir(j,0,2) base.a[i][j]=a[i][j];
        while(p)
        {
            if(p&1) res=res*base;
            base=base*base;
            p>>=1;
        }
        return res;
    }
}S;
map<int,int> mp;
int dfs(int now)
{
    if(now<=1) return now?x:1;
    if(mp.count(now)) return mp[now];
    if(now%2==0) return mp[now]=(dfs(now/2)+dfs(now/2-1))%mod;
    return mp[now]=1ll*x*dfs(now/2)%mod;
}
void solve()
{
    cin>>n>>m;
    S.a[0][1]=S.a[0][2]=S.a[1][0]=S.a[2][1]=1;
    S=S^n;
    x=((S.a[0][0]+S.a[1][1])%mod+S.a[2][2])%mod;
    cout<<dfs(m)<<endl;
    return;
}
int main()
{
    //freopen("1.in","r",stdin);
    //freopen("1.out","w",stdout);
    cin.tie(nullptr)->sync_with_stdio(false);
    if(_mul) cin>>T;
    else T=1;
    while(T--) solve();
    return 0;
}