T=int(input())
mod=998244353
for _ in range(T):
  N,M=map(int, input().split())
  dp=[1,N,max(0,N*(N-1)//2-N)]
  for i in range(M-1):
    ndp=[0]*3
    ndp[0]+=sum(dp)
    ndp[1]+=dp[0]*N+dp[1]*(N-1)+dp[2]*(N-2)
    ndp[2]+=dp[0]*max(0,N*(N-1)//2-N)
    ndp[2]+=dp[1]*max(0,(N-1)*(N-2)//2-(N-2))
    ndp[2]+=dp[2]*max(0,(N-2)*(N-3)//2-(N-4))
    dp=ndp
    for j in range(3):
      dp[j]%=mod 
  print(sum(dp)%mod)