#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define ALL(v) v.begin(),v.end()
typedef long long ll;
 
#include<bits/stdc++.h>
using namespace std;

const int MOD=998244353;
vector<vector<ll>> matrixmul(ll m,vector<vector<ll>> a,vector<vector<ll>> b){
  vector<vector<ll>> c(m,vector<ll>(m,0)); //c:和の単位元
  rep(i,m) rep(j,m) rep(k,m) c[i][j]=(c[i][j]+a[i][k]*b[k][j]%MOD)%MOD;
  return c;
}

//m次正方行列vecのn乗
vector<vector<ll>> matrixpow(ll m,vector<vector<ll>> vec,ll n){
  vector<vector<ll>> ans(m,vector<ll>(m,0));
  rep(i,m) ans[i][i]=1; //ans:積の単位元
  while(n){
    if(n&1) ans=matrixmul(m,ans,vec);
    vec=matrixmul(m,vec,vec);
    n>>=1;
  }
  return ans;
}

int main(){
  ios::sync_with_stdio(false);
  std::cin.tie(nullptr);
  
  int t;
  cin>>t;
  while(t--){
    ll n,m;
    cin>>n>>m;
    vector<vector<ll>> A(3,vector<ll> (3));
    A[0]={1,1,1};
    A[1]={n,n-1,n-2};
    if(n>=4){
      A[2][0]=n*(n-1)/2-n;
      A[2][1]=(n-1)*(n-2)/2-n+2;
      A[2][2]=(n-2)*(n-3)/2-n+4;
    }
    vector<vector<ll>> B=matrixpow(3,A,m);
    ll ans=(B[0][0]+B[1][0]+B[2][0])%MOD;
    cout<<ans<<endl;
  }
  
  return 0;
}