#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int n;
int x[11];
int y[11];
int temp1[11], temp2[11];

int merge_it(int start, int middle, int end)
{
	int i, j, k;
	i = start; j = middle + 1; k = start;
	while (i <= middle&&j <= end)
	{
		if (x[i] < x[j])
		{
			temp1[k] = x[i];
			temp2[k] = y[i];
			k++;
			i++;
		}
		else if (x[i]>x[j])
		{
			temp1[k] = x[j];
			temp2[k] = y[j];
			k++;
			j++;
		}
		else if (x[i] == x[j])
		{
			if (y[i] < y[j])
			{
				temp1[k] = x[i];
				temp2[k] = y[i];
				k++;
				i++;
			}
			else
			{
				temp1[k] = x[j];
				temp2[k] = y[j];
				k++;
				j++;
			}
		}
	}
	while (i <= middle)
	{
			temp1[k] = x[i];
			temp2[k] = y[i];
			k++;
			i++;		
	}
	while (j <= end)
	{
		temp1[k] = x[j];
		temp2[k] = y[j];
		k++;
		j++;
	}
	for (k = start; k <= end; k++)
	{
		x[k] = temp1[k];
		y[k] = temp2[k];
	}
	return 0;
}
int merge_sort(int start, int end)
{
	int middle = start;
	if (start < end)
	{
		middle = (start + end) / 2;
		merge_sort(start, middle);
		merge_sort(middle + 1, end);
	}
	merge_it(start, middle, end);
	return 0;
}
int main()
{
	int test_case, T;
	scanf("%d", &T);
	for (test_case = 1; test_case <= T; test_case++)
	{
		int i;
		scanf("%d", &n);
		for (i = 1; i <= n; i++)
		{
			scanf("%d%d", &x[i], &y[i]);
		}
		//merge_sort(1, n);
		int fail = 1;
		int j;
		for (j = 2; j <= n; j++)
		{
			fail = 1;
			for (i = 1; i < j; i++)
			{
				int two = 0;
				if (x[j] != x[i])
				{
					two++;
				}
				if (y[j] != y[i])
				{
					two++;
				}
				if (two == 1)
				{
					fail = 0;
					break;
				}
			}
			if (fail)
				break;
		}
		if (fail)
			printf("NO\n");
		else
			printf("YES\n");
	}
}