#include <stdio.h>
#include <algorithm>
#define MAX 15
#define INF 1000000000

using namespace std;

struct s {
    int x, y;
};

s inp[MAX];

int main() {
    int qu, n, minx, maxx, miny, maxy, i;
    scanf("%d", &qu);
    while (qu--) {
        scanf("%d", &n);
        minx = INF;
        maxx = -INF;
        miny = INF;
        maxy = -INF;
        for (i = 0; i < n; i++) {
            scanf("%d%d", &inp[i].x, &inp[i].y);
            minx = min(minx, inp[i].x);
            maxx = max(maxx, inp[i].x);
            miny = min(miny, inp[i].y);
            maxy = max(maxy, inp[i].y);
        }
        for (i = 0; i < n; i++) {
            if (inp[i].x != minx && inp[i].x != maxx && inp[i].y != miny &&
                inp[i].y != maxy) {
                break;
            }
        }
        if (i < n) {
            printf("NO\n");
        } else {
            printf("YES\n");
        }
    }
    return 0;
}