T = int(input())
mod = 998244353
def doubling(n, m):
    y = 1
    tmp = m
    bas = n
    while tmp:
        if tmp % 2:
            y *= bas
            y %= mod
        bas *= bas
        bas %= mod
        tmp >>= 1
    return y
for _ in range(T):
    N, K = map(int, input().split())
    print(N*(doubling(2, N*K) - doubling(2, K*(N-1)))%mod)