#include <bits/stdc++.h>
using namespace std;
const long long MOD = 998244353;
int main(){
  int T;
  cin >> T;
  for (int i = 0; i < T; i++){
    int N, M;
    cin >> N >> M;
    if (N == 2){
      vector<long long> dp0(M, 0), dp1(M, 0);
      dp0[0] = 1;
      dp1[0] = 2;
      for (int j = 1; j < M; j++){
        dp0[j] = (dp0[j - 1] + dp1[j - 1]) % MOD;
        dp1[j] = (dp0[j - 1] * 2 + dp1[j - 1]) % MOD;
      }
      cout << (dp0[M - 1] + dp1[M - 1]) % MOD << endl;
    } else {
      vector<long long> dp0(M, 0), dp1(M, 0), dp2(M, 0);
      dp0[0] = 1;
      dp1[0] = N;
      dp2[0] = ((long long) N * (N - 1) / 2 - N) % MOD;
      for (int j = 1; j < M; j++){
        dp0[j] = (dp0[j - 1] + dp1[j - 1] + dp2[j - 1]) % MOD;
        dp1[j] = (dp0[j - 1] * N + dp1[j - 1] * (N - 1) + dp2[j - 1] * (N - 2)) % MOD;
        dp2[j] = (dp0[j - 1] * (((long long) N * (N - 1) / 2 - N) % MOD) + dp1[j - 1] * (((long long) (N - 1) * (N - 2) / 2 - (N - 2)) % MOD) + dp2[j - 1] * (((long long) (N - 2) * (N - 3) / 2 - (N - 4)) % MOD)) % MOD;
      }
      cout << (dp0[M - 1] + dp1[M - 1] + dp2[M - 1]) % MOD << endl;
    }
  }
}