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

int main() {
    int q;
    scanf("%d",&q);
    while(q--){
        int n;
        scanf("%d",&n);
        int a[n][2],i;
        for(i=0;i<n;i++){
            scanf("%d %d",&a[i][0],&a[i][1]);
        }
        //int m,x,e,f,give;
        int maxlength= a[0][0];
        int minlength = a[0][0];
        int minwidth = a[0][1];
        int maxwidth = a[0][1];
        int flag=0;
        for(i=1;i<n;i++){
            if(a[i][1]>maxwidth)
                maxwidth= a[i][1];
                //f= a[i][1];
                //give = i;
                //check=1;
                //break;
            if(a[i][1]<minwidth)
                minwidth= a[i][1];
            
            if(a[i][0]>maxlength)
                maxlength = a[i][0];
            if(a[i][0]<minlength)
                minlength = a[i][0];
        }
        //if(check==1){
        for(i=1;i<n;i++){
            if((a[i][0]<maxlength && a[i][0]>minlength) && (a[i][1]<maxwidth && a[i][1]>minwidth))
                flag=1;
        }
       // }
        
        if(flag==1)
            printf("NO\n");
        else
            printf("YES\n");
           
        
    }

    /* Enter your code here. Read input from STDIN. Print output to STDOUT */    
    return 0;
}