mod = 998244353

t = int(input())
for _ in range(t):
    n, m = map(int, input().split())
    a = pow(pow(2, n, mod) - 1, m, mod)
    a -= pow(2, n * m, mod)
    a += pow(pow(2, m, mod) - 1, n, mod)
    a %= mod
    print(a)