Mod=998244353
T=int(input())
answers=[]
Mod=998244353
facts_max=2*10**5
facts=[]
inv_facts=[]
t=1
for i in range(facts_max+1):
    facts.append(t)
    t=t*(i+1)%Mod
inv_facts.append(pow(facts[facts_max],-1,Mod))
for i in range(facts_max):
    inv_facts.append(inv_facts[-1]*(facts_max-i)%Mod)
inv_facts.reverse()
def comb(n,k):
    if(n<k or n<0):
        return 0
    return facts[n]*inv_facts[k]*inv_facts[n-k]%Mod
for i in range(T):
    N,M=map(int,input().split())
    dp=[1,0,0]
    for i in range(M):
        new_dp=[0]*3
        new_dp[0]=(dp[0]+dp[1]+dp[2])%Mod
        new_dp[1]=(dp[0]*N+dp[1]*(N-1)+dp[2]*(N-2))%Mod
        if(N>2):
            new_dp[2]+=dp[0]*(comb(N,2)-N)
        if(N>=3):
            new_dp[2]+=dp[1]*(comb(N-1,2)-(N-1)+1)
        if(N>=4):
            new_dp[2]+=dp[2]*(comb(N-3,2)-(N-3)+1+N-3)
        dp=[_%Mod for _ in new_dp]
        # print(dp)
    answers.append(sum(dp)%Mod)
for ans in answers:
    print(ans)