from sys import stdin
input = stdin.readline

MOD = 998244353

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

    print((pow((pow(2, N, MOD)-1)%MOD, M, MOD)-(pow(pow(2, M, MOD), N, MOD)-pow(pow(2, M, MOD)-1%MOD, N, MOD)))%MOD)