#include <cstdio>
#include <algorithm>

using namespace std;

const int A = 1000000, N = 1000000, INF = 0x3f3f3f3f;
int r, c;

struct Node
{
	int a, x, y;
	bool operator < (const Node &t) const
	{
		return a < t.a;
	}
}node[A + 5];
int cntn;

void init()
{
	scanf("%d %d", &r, &c);
	for(int i = 1; i <= r; i++)
	{
		for(int j = 1; j <= c; j++)
		{
			int x;
			scanf("%d", &x);
			node[++cntn] = (Node){x, i, j};
		}
	}
}

struct Rge
{
	int l, r;
}rge[N + 5];
void solve()
{
	sort(node + 1, node + cntn + 1);
	for(int i = 1; i <= c; i++)
	{
		rge[i].l = INF;
		rge[i].r = -INF;
	}
	for(int i = 1; i <= r * c; i++)
	{
		int x = node[i].x, y = node[i].y;
		rge[y].l = min(rge[y].l, x);
		rge[y].r = max(rge[y].r, x);
		if((y > 1 && rge[y].l < rge[y - 1].r) || (y < c && rge[y].r > rge[y + 1].l))
		{
			printf("%d\n", i - 1);
			return;
		}
	}
	printf("%d\n", r * c);
}

void clr()
{
	cntn = 0;
}

int main()
{
	int T;
	scanf("%d", &T);
	while(T--)
	{
		init();
		solve();
		clr();
	}
	return 0;
}