#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <iostream>
#include <iomanip>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <cmath>
#include <cassert>
#include <ctime>
#include <utility>
#include <random>
#include <tuple>
#include <bitset>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
typedef long long ll;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repr(i, n) for (int i = (int)(n) - 1; i >= 0; i--)
#define repk(i, k, n) for (int i = k; i < (int)(n); i++)
#define all(v) v.begin(), v.end()
#define mod1 1000000007
#define mod2 998244353
#define mod3 100000007
#define vi vector<int>
#define vs vector<string>
#define vc vector<char>
#define vl vector<ll>
#define vb vector<bool>
#define vvi vector<vector<int>>
#define vvc vector<vector<char>>
#define vvl vector<vector<ll>>
#define vvb vector<vector<bool>>
#define vvvi vector<vector<vector<int>>>
#define vvvl vector<vector<vector<ll>>>
#define pii pair<int,int>
#define pil pair<int,ll>
#define pli pair<ll, int>
#define pll pair<ll, ll>
#define vpii vector<pair<int,int>>
#define vpll vector<pair<ll,ll>>
#define vvpii vector<vector<pair<int,int>>>
#define vvpll vector<vector<pair<ll,ll>>>

template<typename T> void debug(T e){
    cerr << e << endl;
}

template<typename T> void debug(vector<T> &v){
    rep(i, v.size()){
        cerr << v[i] << " ";
    }
    cerr << endl;
}

template<typename T> void debug(vector<vector<T>> &v){
    rep(i, v.size()){
        rep(j, v[i].size()){
            cerr << v[i][j] << " ";
        }
        cerr << endl;
    }
}

template<typename T> void debug(vector<pair<T, T>> &v){
    rep(i,v.size()){
        cerr << v[i].first << " " << v[i].second << endl;
    }
}

template<typename T> void debug(set<T> &st){
    for (auto itr = st.begin(); itr != st.end(); itr++){
        cerr << *itr << " ";
    }
    cerr << endl;
}

template<typename T> void debug(multiset<T> &ms){
    for (auto itr = ms.begin(); itr != ms.end(); itr++){
        cerr << *itr << " ";
    }
    cerr << endl;
}

template<typename T> void debug(map<T, T> &mp){
    for (auto itr = mp.begin(); itr != mp.end(); itr++){
        cerr << itr->first << " " << itr->second << endl;
    }
}

void debug_out(){
    cerr << endl;
}

template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T){
    cerr << H << " ";
    debug_out(T...);
}

ll my_pow(ll x, ll n, ll mod){
    //　繰り返し二乗法．x^nをmodで割った余り．
    ll ret;
    if (n == 0){
        ret = 1;
    }
    else if (n % 2 == 1){
        ret = (x * my_pow((x * x) % mod, n / 2, mod)) % mod;
    }
    else{
        ret = my_pow((x * x) % mod, n / 2, mod);
    }
    return ret;
}

ll inv(ll x, ll mod){
    return my_pow(x, mod - 2, mod);
}

int main(){
    ll H, W;
    cin >> H >> W;
    vl fact(500005, 0);
    fact[0] = 1;
    for (ll i = 0; i < 500003; i++){
        fact[i + 1] = (fact[i] * (i + 1)) % mod2;
    }
    vl fact_inv(500005, 0);
    for (ll i = 0; i < 500004; i++){
        fact_inv[i] = inv(fact[i], mod2);
    }
    auto comb = [fact, fact_inv](ll n, ll r){
        ll ret;
        if (n < r){
            ret = 0;
        }
        else if (r < 0){
            ret = 0;
        }
        else{
            ret = (fact[n] * ((fact_inv[n - r] * fact_inv[r]) % mod2)) % mod2;
        }
        return ret;
    };
    vl h_vec(H + 1);
    vl w_vec(W + 1);
    for (ll i = 0; i <= H; i++){
        h_vec[i] = comb(i, H - 2 * (H - i));
    }
    for (ll i = 0; i <= W; i++){
        w_vec[i] = comb(i, W - 2 * (W - i));
    }
    //debug(h_vec);
    //debug(w_vec);
    for (ll i = 0; i <= H; i++){
        h_vec[i] = (h_vec[i] * fact_inv[i]) % mod2;
    }
    for (ll i = 0; i <= W; i++){
        w_vec[i] = (w_vec[i] * fact_inv[i]) % mod2;
    }
    vl conv = convolution<998244353>(h_vec, w_vec);
    ll ans = 0;
    for (ll i = 0; i <= H + W; i++){
        ans = (ans + (conv[i] * fact[i]) % mod2) % mod2;
    }
    cout << ans << endl;
}