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

const int Mod = 998244353;
typedef long long LL;

struct Matrix{
    int a[3][3];

    void init(){
        memset(a, 0, sizeof(a));
    }

    Matrix operator* (Matrix &w){
        static Matrix c;
        c.init();
        for(int i = 0; i < 3; i ++){
            for(int j = 0; j < 3; j ++){
                for(int k = 0; k < 3; k ++){
                    c.a[i][j] = (c.a[i][j] + 1ll * a[i][k] * w.a[k][j]) % Mod;
                }
            }
        }

        return c;
    }
};

Matrix qpow(Matrix a, int k){
    Matrix ans = a;
    k --;
    while(k){
        if(k & 1)ans = ans * a;
        k >>= 1;
        a = a * a;
    }

    return ans;
}

Matrix g = {{{0, 1, 1}, {1, 0, 0}, {0, 1, 0}}};

int ans;

map<int, int> f;

int dp(int x){
    if(x == 0)return 1;
    else if(x == 1)return ans;
    if(f.count(x))return f[x];

    if(x & 1)return f[x] = 1ll * ans * dp(x / 2) % Mod;
    else return f[x] = (dp(x / 2) + dp(x / 2 - 1)) % Mod;
}

int main(){
    int n, m;
    scanf("%d%d", &n, &m);

    Matrix T = qpow(g, n);
    ans = ((LL)T.a[0][0] + T.a[1][1] + T.a[2][2]) % Mod;

    printf("%d\n", dp(m));
}