#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	int T;
	cin >> T;
	while (T--)
	{
		int n, m;
		cin >> n >> m;
		int total = n * m;
		vector < pair < int, int >>pos(total);
		vector < vector < int >>grid(n, vector < int >(m));
		for (int i = 0; i < n; i++)
		{
			for (int j = 0; j < m; j++)
			{
				cin >> grid[i][j];
				pos[grid[i][j]] =
				{
				i, j};
			}
		}
		vector < int >dp(total, 1);
		vector < int >prev(total, -1);
		int dirs[4][2] = { {-1, 0}, {1, 0}, {0, -1}, {0, 1} };
		for (int a = 0; a < total; a++)
		{
			int x = pos[a].first;
			int y = pos[a].second;
			for (int d = 0; d < 4; d++)
			{
				int nx = x + dirs[d][0];
				int ny = y + dirs[d][1];
				if (nx >= 0 && nx < n && ny >= 0 && ny < m)
				{
					int b = grid[nx][ny];
					if (b < a)
					{
						if (dp[b] + 1 > dp[a])
						{
							dp[a] = dp[b] + 1;
							prev[a] = b;
						}
						else if (dp[b] + 1 == dp[a])
						{

							if (prev[a] == -1 || b < prev[a])
							{
								prev[a] = b;
							}
						}
					}
				}
			}
		}

		int max_len = 0;
		for (int a = 0; a < total; a++)
		{
			if (dp[a] > max_len)
			{
				max_len = dp[a];
			}
		}

		vector < int >candidates;
		for (int a = 0; a < total; a++)
		{
			if (dp[a] == max_len)
			{
				candidates.push_back(a);
			}
		}

		vector < int >best_path;
	  for (auto a:candidates)
		{
			vector < int >path;
			int current = a;
			while (current != -1)
			{
				path.push_back(current);
				current = prev[current];
			}
			reverse(path.begin(), path.end());
			if (best_path.empty() || path < best_path)
			{
				best_path = path;
			}
		}

		cout << best_path.size() << "\n";
		for (int i = 0; i < best_path.size(); i++)
			cout << best_path[i] << (i < best_path.size() - 1 ? " " : "\n");
	}
}