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

using ll = long long;
using pii = pair<int, int>;
using vi = vector<int>;
using vll = vector<long long>;
using vvi = vector<vi>;
using vs = vector<string>;
using vc = vector<char>;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define all(a) (a).begin(), (a).end()
template<class T> using min_pq = priority_queue<T, vector<T>, greater<T>>;

const int INF = 1e9;
const ll LINF = 1e18;
const ll mod=998244353;
const long long MOD =998244353 ;
const int MAX_C = 2000005;
long long fact[MAX_C], inv_fact[MAX_C];

long long power(long long a, long long b, long long m) {
    long long res = 1;
    a %= m;
    while (b > 0) {
        if (b & 1) res = res * a % m;
        a = a * a % m;
        b >>= 1;
    }
    return res;
}

void init_comb() {
    fact[0] = 1;
    for (int i = 1; i < MAX_C; i++) fact[i] = fact[i-1] * i % MOD;
    inv_fact[MAX_C-1] = power(fact[MAX_C-1], MOD-2, MOD);
    for (int i = MAX_C-2; i >= 0; i--) {
        inv_fact[i] = inv_fact[i+1] * (i+1) % MOD;
    }
}

long long nCk(ll n, int k) {
    if (k < 0 || k > n) return 0;
    if(n<MAX_C) return fact[n] * inv_fact[k] % MOD * inv_fact[n-k] % MOD;
    else{
        ll re=1;
        for(ll i=0;i<k;i++) re=re*((n-i)%MOD)%MOD;
        return re*inv_fact[k]%MOD;
        }
}

int main() {
    init_comb();
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int n,m;
    cin >> n >> m;
    ll ans=0;
    vll two(7001,1);
    ll want=1;
    rep(i,7000){
        two[i+1]*=want;
        want*=2;
        want%=mod;
    }
    vector<vector<bool>> seen(n+1,vector<bool>(m+1,false));
    for(int i=1;i<=n;i++)for(int j=1;j<=m;j++){
        ll cnt=two[i+j-2];
        ll now=((cnt*(n-i+1))%mod)*((n-j+1)%mod);
        if(i==n&&j*2==m){
            now/=2;
        }
        if(i*2==n&&j==m) now/=2;
        ans+=now;
        ans%=mod;
    }
    cout << ans << endl;
    
}