import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;

public class Main {
	public static void main(String[] args) throws Exception {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int t = Integer.parseInt(br.readLine());
		int mod = 998244353;
		PrintWriter pw = new PrintWriter(System.out);
		for (int z = 0; z < t; z++) {
			String[] sa = br.readLine().split(" ");
			int n = Integer.parseInt(sa[0]);
			int m = Integer.parseInt(sa[1]);

			long[][] dp = new long[3][m];
			dp[0][0] = 1;
			dp[1][0] = n;
			if (n >= 4) {
				dp[2][0] = (n - 3) * (n - 2) / 2 + (n - 3);
			}

			long n21 = Math.max(dp[2][0] - (n - 3), 0);
			long n22 = Math.max(dp[2][0] - (n - 3) * 2 + 1, 0);

			for (int i = 1; i < m; i++) {
				dp[0][i] += dp[0][i - 1] + dp[1][i - 1] + dp[2][i - 1];
				dp[0][i] %= mod;

				dp[1][i] += dp[0][i - 1] * n % mod;
				dp[1][i] += dp[1][i - 1] * (n - 1) % mod;
				dp[1][i] += dp[2][i - 1] * (n - 2) % mod;
				dp[1][i] %= mod;

				if (n >= 4) {
					dp[2][i] += dp[0][i - 1] * dp[2][0] % mod;
					dp[2][i] += dp[1][i - 1] * n21 % mod;
					dp[2][i] += dp[2][i - 1] * n22 % mod;
					dp[2][i] %= mod;
				}
			}
			long ans = dp[0][m - 1] + dp[1][m - 1] + dp[2][m - 1];
			ans %= mod;
			pw.println(ans);
		}
		pw.flush();
		br.close();
	}
}