#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */    
    int q, n, x ,y;
    scanf("%d", &q);
    int maxX, maxY, minX, minY;
    for(int i = 0; i < q; i++){
        scanf("%d", &n);
        scanf("%d%d", &x, &y);
        maxX = x, maxY = y; minX = x, minY = y;
        for(int y = 1; y < q; y++){
            scanf("%d%d", &x, &y);
            if (maxX < x && (maxY == y || minY == y))
                maxX = x;
            else if (maxY < y && (maxY == x || minY == x))
                maxY = y;
            else if (minX > x && (minY == y || maxY == y))
                minX = x;
            else if (minY > y && (minY == x || maxY == x))
                minY = y;
            else {
                printf("NO\n");
                break;
            }
            if (y = q - 1)
                printf("YES\n");
        }
    }
    return 0;
}