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

const int mod = 998244353;
const int N = 4e5 + 5;
int fac[N], ifac[N];
int inv(int x)
{
	int res = 1, y = mod - 2;
	while (y)
	{
		if (y & 1) res = 1ll * res * x % mod;
		x = 1ll * x * x % mod;
		y >>= 1;
	}
	return res;
}
int binom(int x, int y)
{
	if (x < 0 or y < 0 or x < y) return 0;
	return 1ll * fac[x] * ifac[y] % mod * ifac[x - y] % mod;
}
int cal(int x, int y)
{
	int ret = 1ll * binom(x + y - 2, x - 1) * binom(x + y - 2, y - 1) % mod;
	ret = (ret + mod - 1ll * binom(x + y - 2, x - 2) * binom(x + y - 2, y - 2) % mod) % mod;
	return ret;
}

const int P = 998244353;
using i64 = long long;
using Poly = vector<int>;
#define MUL(a, b) (i64(a) * (b) % P)
#define ADD(a, b) (((a) += (b)) >= P ? (a) -= P : 0)
#define SUB(a, b) (((a) -= (b)) < 0 ? (a) += P : 0)
Poly getInv(int L)
{
    Poly inv(L);
    inv[1] = 1;
    for (int i = 2; i < L; i++)
        inv[i] = MUL((P - P / i), inv[P % i]);
    return inv;
}
int POW(i64 a, int b = P - 2, i64 x = 1)
{
    for (; b; b >>= 1, a = a * a % P)
        if (b & 1)
            x = x * a % P;
    return x;
}
namespace NTT
{
    const int g = 3;
    Poly Omega(int L)
    {
        int wn = POW(g, P / L);
        Poly w(L);
        w[L >> 1] = 1;
        for (int i = L / 2 + 1; i < L; i++)
            w[i] = MUL(w[i - 1], wn);
        for (int i = L / 2 - 1; i >= 1; i--)
            w[i] = w[i << 1];
        return w;
    }
    auto W = Omega(1 << 20);
    void DIF(int *a, int n)
    {
        for (int k = n >> 1; k; k >>= 1)
            for (int i = 0, y; i < n; i += k << 1)
                for (int j = 0; j < k; j++)
                    y = a[i + j + k], a[i + j + k] = MUL(a[i + j] - y + P, W[k + j]), ADD(a[i + j], y);
    }
    void IDFT(int *a, int n)
    {
        for (int k = 1; k < n; k <<= 1)
            for (int i = 0, x, y; i < n; i += k << 1)
                for (int j = 0; j < k; j++)
                    x = a[i + j], y = MUL(a[i + j + k], W[k + j]),
                    a[i + j + k] = x - y < 0 ? x - y + P : x - y, ADD(a[i + j], y);
        int Inv = P - (P - 1) / n;
        for (int i = 0; i < n; i++)
            a[i] = MUL(a[i], Inv);
        reverse(a + 1, a + n);
    }
}
namespace Polynomial
{
    int norm(int n) { return 1 << (__lg(n - 1) + 1); }
    void norm(Poly &a)
    {
        if (!a.empty())
            a.resize(norm(a.size()), 0);
        else
            a = {0};
    }
    void DFT(Poly &a) { NTT::DIF(a.data(), a.size()); }
    void IDFT(Poly &a) { NTT::IDFT(a.data(), a.size()); }
    Poly &dot(Poly &a, Poly &b)
    {
        for (int i = 0; i < a.size(); i++)
            a[i] = MUL(a[i], b[i]);
        return a;
    }
    Poly operator*(Poly a, Poly b)
    {
        int n = a.size() + b.size() - 1, L = norm(n);
        if (a.size() <= 8 || b.size() <= 8)
        {
            Poly c(n);
            for (int i = 0; i < a.size(); i++)
                for (int j = 0; j < b.size(); j++)
                    c[i + j] = (c[i + j] + (i64)a[i] * b[j] % P) % P;
            return c;
        }
        a.resize(L), b.resize(L);
        DFT(a), DFT(b), dot(a, b), IDFT(a);
        return a.resize(n), a;
    }
}
using namespace Polynomial;

int main() 
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	
	fac[0] = 1;
	for (int i = 1; i <= 400000; i++)
		fac[i] = 1ll * fac[i - 1] * i % mod;
	ifac[400000] = inv(fac[400000]);
	for (int i = 399999; i >= 0; i--)
		ifac[i] = 1ll * ifac[i + 1] * (i + 1) % mod;
	
	int n, m;
	cin >> n >> m;
	int ans = 2;
	for (int i = 1; i <= n; i++) ans = (ans + 1ll * (n - i + 1) * cal(i, m) % mod) % mod;
	for (int i = 1; i < m; i++) ans = (ans + 1ll * (m - i) * cal(n, i) % mod) % mod;
	
//	for (int i = 1; i <= n; i++)
//	{
//		for (int j = 1; j < m; j++) ans = (ans + cal(i, j)) % mod;
//	}
//	for (int i = 1; i < m; i++)
//	{
//		for (int j = 1; j < n; j++) ans = (ans + cal(j, i)) % mod;
//	}
{
	Poly f(n + 1), g(m);
	for (int i = 1; i <= n; i++) f[i] = 1ll * ifac[i - 1] * ifac[i - 1] % mod;
	for (int i = 1; i < m; i++) g[i] = 1ll * ifac[i - 1] * ifac[i - 1] % mod;
	auto h = f * g;
	int tmp = 0;
	for (int i = 2; i <= n + m - 1; i++) tmp = (tmp + 1ll * h[i] * fac[i - 2] % mod * fac[i - 2] % mod) % mod;
	ans = (ans + tmp) % mod;
	 
	f.assign(n + 1, 0);
	g.assign(m, 0);
	for (int i = 2; i <= n; i++) f[i] = 1ll * ifac[i - 2] * ifac[i] % mod;
	for (int i = 2; i < m; i++) g[i] = 1ll * ifac[i - 2] * ifac[i] % mod;
	h = f * g;
	tmp = 0;
	for (int i = 2; i <= n + m - 1; i++) tmp = (tmp + 1ll * h[i] * fac[i - 2] % mod * fac[i - 2] % mod) % mod;
	ans = (ans + mod - tmp) % mod;
}
{
	Poly f(n), g(m);
	for (int i = 1; i < n; i++) f[i] = 1ll * ifac[i - 1] * ifac[i - 1] % mod;
	for (int i = 1; i < m; i++) g[i] = 1ll * ifac[i - 1] * ifac[i - 1] % mod;
	auto h = f * g;
	int tmp = 0;
	for (int i = 2; i < n + m - 1; i++) tmp = (tmp + 1ll * h[i] * fac[i - 2] % mod * fac[i - 2] % mod) % mod;
	ans = (ans + tmp) % mod;
	 
	f.assign(n, 0);
	g.assign(m, 0);
	for (int i = 2; i < n; i++) f[i] = 1ll * ifac[i - 2] * ifac[i] % mod;
	for (int i = 2; i < m; i++) g[i] = 1ll * ifac[i - 2] * ifac[i] % mod;
	h = f * g;
	tmp = 0;
	for (int i = 2; i < n + m - 1; i++) tmp = (tmp + 1ll * h[i] * fac[i - 2] % mod * fac[i - 2] % mod) % mod;
	ans = (ans + mod - tmp) % mod;
}
	cout << ans << '\n';
}