class Combination:

    def __init__(self, MX=10**6, MOD=998244353):
        self.MX = MX
        self.MOD = MOD
        self.fact = [1] * (MX + 1)
        self.inv = [1] * (MX + 1)
        self.f_inv = [1] * (MX + 1)
        for i in range(2, MX + 1):
            self.fact[i] = (self.fact[i - 1] * i) % self.MOD
            self.inv[i] = ( - (self.MOD // i) * (self.inv[self.MOD % i])) % self.MOD
            self.f_inv[i] = (self.f_inv[i - 1] * self.inv[i]) % self.MOD
    
    def invs(self, n):
        if n <= self.MX:
            return self.inv[n]
        else:
            return pow(n, self.MOD - 2, self.MOD)
    
    def p(self, n, r):
        if r > n or r < 0:
            return 0
        return (self.fact[n] * self.f_inv[r]) % self.MOD
    
    def c(self, n, r):
        if r > n or r < 0:
            return 0
        return (self.fact[n] * self.f_inv[r] * self.f_inv[n - r]) % self.MOD

MOD = 998244353
com = Combination()

def solve():
    N, M = map(int, input().split())

    dp = [1, 0, 0]
    for i in range(M):
        ndp = [0, 0, 0]
        if N >= 4:
            ndp[2] += dp[2] * (com.c(N - 2, 2) - (N - 4))
            ndp[2] += dp[1] * (com.c(N - 1, 2) - (N - 2))
            ndp[2] += dp[0] * (com.c(N, 2) - N)
        ndp[1] += dp[2] * (N - 2)
        ndp[1] += dp[1] * (N - 1)
        ndp[1] += dp[0] * N
        ndp[0] += sum(dp)
        ndp[0] %= MOD
        ndp[1] %= MOD
        ndp[2] %= MOD
        dp = ndp
    print(sum(dp) % MOD)

T = int(input())
for _ in range(T):
    solve()