MOD=998244353
T=int(input())
for _ in range(T):
    N,M=map(int,input().split())

    # Sum[i=0,..,k] C(k,i)(-1)^i 2^(k-i)M = (2^M-1)^k

    # Sum[k=1,..,N] C(N,k) * (2^M-1)^k * k = x * d/dx (1+x)^N
    # = Nx(1+x)^{N-1} = N*2^{M(N-1)} * (2^M-1)

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

    print(ans)