import sys
from itertools import permutations
from heapq import heappop,heappush
from collections import deque
import random
import bisect

input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())

def cmb(n, r, mod):
    if ( r<0 or r>n ):
        return 0
    return (g1[n] * g2[r] % mod) * g2[n-r] % mod


mod = 998244353
N = 2*10**5
g1 = [1]*(N+1)
g2 = [1]*(N+1)
inverse = [1]*(N+1)

for i in range( 2, N + 1 ):
    g1[i]=( ( g1[i-1] * i ) % mod )
    inverse[i]=( ( -inverse[mod % i] * (mod//i) ) % mod )
    g2[i]=( (g2[i-1] * inverse[i]) % mod )
inverse[0]=0

def solve(N,M):
    if N <= 3:
        dp = [1,0]
        for _ in range(M):
            dp = [(dp[0]+dp[1]) % mod,(dp[0]*N+dp[1]*(N-1)) % mod]
        return (dp[0] + dp[1]) % mod
    
    dp = [1,0,0]
    for _ in range(M):
        a = N*(N-1)//2 - N
        b = N*(N-1)//2 - N - (N-1) + 2
        c = N*(N-1)//2 - 2*(N-1) + 1 - (N-4)
        dp = [
            (dp[0]+dp[1]+dp[2]) % mod,
            (dp[0]*N + dp[1]*(N-1) + dp[2]*(N-2)) % mod,
            (dp[0]*a % mod + dp[1] * b % mod + dp[2] * c % mod) % mod
        ]
    
    return sum(dp) % mod

for _ in range(int(input())):
    N,M = mi()
    print(solve(N,M))