import java.util.*;


public class Main {
    static int[][] map;
    static int[][] dp;
    static int N;
    static int M;
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int T;
        T = sc.nextInt();
        for(int i=0;i<T;i++){
            N = sc.nextInt();
            M = sc.nextInt();
            map = new int[N+1][N+1];
            dp = new int[N][N];
            for(int j=0;j<N;j++){
                for(int k=0;k<N;k++){
                    map[j][k] = sc.nextInt();
                }

            }

            int max =0;
            for(int n=0;n<N-1;n++){
                for(int m=0;m<N-1;m++){
                    dp[n][m] = map[n][m]+map[n][m+1]+map[n+1][m]+map[n+1][m+1];
                    if(dp[n][m]>max)
                        max = dp[n][m];
                }
            }
            System.out.println(max);
        }


    }



}