#include <cstdio>
#include <algorithm>

using namespace std;

int t, n, m, i, j, ans;
int a[1005][1005], f[1005][1005];

int main() {
	scanf("%d", &t);
	while (t--) {
		scanf("%d%d", &n, &m);
		for (int i = 1; i <= n; i++) {
			for (int j = 1; j <= m; j++) {
				scanf("%d", &a[i][j]);
			}
		}
		ans = a[n][m];
		for (int i = 1; i <= n; i++) {
			for (int j = 1; j <= m; j++) {
				f[i][j] = f[i - 1][j] + f[i][j - 1] - f[i - 1][j - 1] + a[n - i + 1][m - j + 1];
				ans = max(ans, f[i][j]);
			}
		}
		printf("%d\n", ans);
	}
	return 0;
}