#include <bits/stdc++.h>
#define inf 1234567890123456789LL
using namespace std;

using cat = long long;

int main() {
	cin.sync_with_stdio(0);
	cin.tie(0);
	int T;
	cin >> T;
	for(int t = 0; t < T; t++) {
		int N, M;
		cin >> N >> M;
		vector< vector<int> > G(N, vector<int>(M));
		for(int i = 0; i < N*M; i++) cin >> G[i/M][i%M];

		// compute max. sums from each central cell in all directions
		vector< vector<cat> > mx_up(N, vector<cat>(M));
		vector< vector<cat> > mx_down(N, vector<cat>(M));
		vector< vector<cat> > mx_lft(N, vector<cat>(M));
		vector< vector<cat> > mx_rt(N, vector<cat>(M));
		for(int i = 0; i < N; i++) {
			cat mi = 0, sum = 0;
			for(int j = 0; j < M; j++) {
				if(j > 0) mx_lft[i][j] = sum-mi;
				mi = min(mi, sum);
				sum += G[i][j];
			}
			mi = sum = 0;
			for(int j = M-1; j >= 0; j--) {
				if(j < M-1) mx_rt[i][j] = sum-mi;
				mi = min(mi, sum);
				sum += G[i][j];
			}
		}
		for(int i = 0; i < M; i++) {
			cat mi = 0, sum = 0;
			for(int j = 0; j < N; j++) {
				if(j > 0) mx_up[j][i] = sum-mi;
				mi = min(mi, sum);
				sum += G[j][i];
			}
			mi = sum = 0;
			for(int j = N-1; j >= 0; j--) {
				if(j < N-1) mx_down[j][i] = sum-mi;
				mi = min(mi, sum);
				sum += G[j][i];
			}
		}

		cat ans = -inf;
		// bruteforce all central cells
		for(int i = 1; i < N-1; i++) for(int j = 1; j < M-1; j++) {
			cat sum = G[i][j] + mx_down[i][j] + mx_up[i][j] + mx_lft[i][j] + mx_rt[i][j];
			ans = max(ans, sum);
		}
		cout << ans << "\n";
	}
	return 0;
}