"""

https://yukicoder.me/problems/no/2529

0個
1個置かれている場合

2個の場合

避けて置く。その内、隣接するのは…

XOXOOO -> 2
XOOXOO -> 2

XOXOOOO -> 3
XOOXOOO -> 3

一緒か

XOXO -> 

"""

import math
import sys
from sys import stdin

def modfac(n, MOD):
 
    f = 1
    factorials = [1]
    for m in range(1, n + 1):
        f *= m
        f %= MOD
        factorials.append(f)
    inv = pow(f, MOD - 2, MOD)
    invs = [1] * (n + 1)
    invs[n] = inv
    for m in range(n, 1, -1):
        inv *= m
        inv %= MOD
        invs[m - 1] = inv
    return factorials, invs


def modnCr(n,r): #上で求めたfacとinvsを引数に入れるべし(上の関数で与えたnが計算できる最大のnになる)
    return fac[n] * inv[n-r] * inv[r] % mod

mod = 998244353
fac,inv = modfac(10**6+100,mod)

TT = int(stdin.readline())

for loop in range(TT):

    M,N = map(int,stdin.readline().split())

    dp = [1,0,0]
    
    for i in range(N):

        ndp = [0,0,0]

        ndp[0] = sum(dp) % mod

        ndp[1] = (dp[0] * M + dp[1] * (M-1) + dp[2] * (M-2)) % mod


        ndp[2] = dp[0] * (M * (M-1)//2 - M)
        ndp[2] += dp[1] * ( (M-1)*(M-2)//2 - (M-2))
        ndp[2] += dp[2] * ((M-2)*(M-3)//2 - (M-4))

        ndp[2] %= mod

        dp = ndp

        if M <= 3:
            dp[2] = 0

    print (sum(dp) % mod )