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")
#######################################################################

mod = 998244353
for _ in range(ni()):
    n, m = na()
    ans = pow(pow(2, n, mod) - 1, m, mod) - (pow(2, m * n, mod) - pow(pow(2, m, mod) - 1, n, mod))
    print(ans % mod)