#nullable enable

#region
var _input = Array.Empty<string>();
var _iter = 0;
string String()
{
    while (_iter >= _input.Length) (_input, _iter) = (Console.ReadLine()!.Split(' '), 0);
    return _input[_iter++];
}
T I<T>() where T : IParsable<T> => T.Parse(String(), null);
#endregion

const int Mod = 998244353;

var h = I<long>();
var w = I<long>();
var ans = Power(2, (h - 1) * (w - 1) + 2, Mod);
Console.WriteLine(ans);

static long Power(long v, long p, long mod)
{
    var (res, k) = (1L, v);
    while (p > 0)
    {
        if ((p & 1) > 0) res = res * k % mod;
        k = k * k % mod;
        p >>= 1;
    }
    return res;
}