#if defined(_USE_PCH_)
#include "pch.hpp"
#else
#include <bits/stdc++.h>
#endif
#define RNG(V_, A_, B_, ...) for(int V_=(A_), V_##_END=(B_) __VA_OPT__(,) __VA_ARGS__; V_<=V_##_END; V_++)
#define IRNG(V_, A_, B_, ...) for(int V_=(A_), V_##_END=(B_) __VA_OPT__(,) __VA_ARGS__; V_>=V_##_END; V_--)
#ifdef _WIN32
#define long int64_t
#endif
#define fi first
#define se second
#define _UN using namespace
using namespace std;
typedef pair<int,int> pii;
typedef __int128 i128;
const int MOD=998244353;
void addto(long& x,long y){ x=(x+y)%MOD; }
struct Mat{
    long A[3][3];
    void z(){ memset(&A,0,sizeof(A)); }
    Mat operator*(const Mat& o) const{
        Mat r; r.z();
        RNG(k,0,2){
            RNG(i,0,2){
                RNG(j,0,2) addto(r.A[i][j],A[i][k]*o.A[k][j]);
            }
        }
        return r;
    }
};
int n,m;
Mat qpow(Mat x,int p){
    Mat ret=x;
    for(p--; p; p>>=1,x=x*x){
        if(p&1) ret=ret*x;
    }
    return ret;
}
int main(){
#if defined(_LOCAL_)
    freopen("in","r",stdin);
//  freopen("out","w",stdout);
//  freopen("/dev/null","w",stderr);
#else
//  freopen("0.in","r",stdin);
//  freopen("0.out","w",stdout);
#endif
    ios::sync_with_stdio(false),cin.tie(nullptr),cout.tie(nullptr);
    cin>>n>>m;
    Mat A=qpow(Mat{{{0,1,1},{1,0,0},{0,1,0}}},n);
    auto a=(A.A[0][0]+A.A[1][1]+A.A[2][2]);
    unordered_map<int,long> mp;
    function<long(int)> f=[&](int x){
        if(mp.count(x)) return mp[x];
        if(!x) return 1l;
        else if(x&1) return a*f(x/2)%MOD;
        else return mp[x]=(f(x/2)+f(x/2-1))%MOD;
    };
    cout<<f(m)<<"\n";
}