MOD = 998244353

T = int(input())
for _ in range(T):
    N, M = map(int, input().split())

    ans = pow(pow(2, N, MOD) - 1, M, MOD)
    ans -= pow(pow(2, M, MOD), N, MOD) - pow(pow(2, M, MOD) - 1, N, MOD)
    print(ans)