#面白い！

mod = 998244353

def solve():
    N, M = map(int, input().split())
    # ans = (2 ** N - 1) ** M + (2 ** M - 1) ** N - (2 ** M) ** N
    ans = pow(pow(2, N, mod) - 1, M, mod) + pow(pow(2, M, mod) - 1, N, mod) - pow(pow(2, M, mod), N, mod)
    print(ans % mod)

for _ in range(int(input())):
    solve()