Maximum sum of hour glass

//Maximum sum of hour glass

import java.io.*;
import java.util.*;

class GFG {
    public static void main(String args[]) throws IOException {
        BufferedReader read = new BufferedReader(new InputStreamReader(System.in));
        int t = Integer.parseInt(read.readLine());

        while(t-- > 0) {
            String s[] = read.readLine().split(" ");
            int N = Integer.parseInt(s[0]);
            int M = Integer.parseInt(s[1]);
            int Mat[][] = new int[N][M];

            for(int i = 0; i < N; i++) {
                String S[] = read.readLine().split(" ");

                for(int j = 0; j < M; j++) {
                    Mat[i][j] = Integer.parseInt(S[j]);
                }
            }
            Solution ob = new Solution();
            System.out.println(ob.findMaxSum(N, M, Mat));
        }
    }
}

class Solution {
    int findMaxSum(int n, int m, int mat[][]) {
        if(n < 3 || m < 3) {
            return -1;
        }
        
        int ans = Integer.MIN_VALUE;
        
        for(int i = 2; i < n; i++) {
            int sum = 0;
            
            for(int j = 1; j < m - 1; j++) {
                sum = mat[i][j - 1] + mat[i - 2][j - 1] + mat[i - 1][j] + mat[i][j] + mat[i - 2][j]
                    + mat[i][j + 1] + mat[i - 2][j + 1];
                ans = Math.max(ans, sum);
            }
        }
        
        return ans;
    }
};