M=998244353


def main():
    t = int(input())
    for _ in range(t):
        n,m=map(int,input().split())
        x = pow(2, m, M)
        y = pow(2, n, M)
        print((pow(y-1, m, M)+pow(x-1, n, M)-pow(x, n, M))%M)


if __name__ == "__main__":
    main()