import sys
input = lambda :sys.stdin.readline()[:-1]
ni = lambda :int(input())
na = lambda :list(map(int,input().split()))
yes = lambda :print("yes");Yes = lambda :print("Yes");YES = lambda : print("YES")
no = lambda :print("no");No = lambda :print("No");NO = lambda : print("NO")
#######################################################################

def naive(h, w):
    ans = 0
    for bit in range(1 << (h * w)):
        ok = 1
        for i in range(1, h):
            for j in range(1, w):
                a = 0
                for x in range(i):
                    for y in range(j):
                        a ^= bit >> (w * x + y) & 1
                for x in range(i, h):
                    for y in range(j, w):
                        a ^= bit >> (w * x + y) & 1
                if a == 0:
                    ok = 0
                    break
            if ok == 0:
                break
        ans += ok
    return ans


# for h in range(2, 5):
#     for w in range(h, 8):
#         print(h, w, naive(h, w), pow(2, (h - 1) * (w - 1) + 2))

h, w = na()
print(pow(2, (h-1) * (w-1) + 2, 998244353))