#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int q;
    cin >> q;
    while(q--)
        {
        int n;
        cin >> n;
        int j = 0, flag, k=0;
        while(n--)
            {
            int x, y;
            cin >> x >> y;
            j = max(x,y);
            k = max(k,j);
            
             if(x == k)
                 {
                 if(y >=0 && y <= k)
                     flag = 0;
                }
            else if (y ==k)
                {
                if(x >=0 && x >= k)
                    flag = 0;
            }
            else if( (x > 0 && y!=k) || (x!=k && y > 0))
                {
                flag = 1;
                    break;
                }
                   
                
           }
        if(flag == 1)
                {
                cout << "NO" << endl;
                }
            else
                {
                cout << "YES" << endl;
             }
        
    }
    return 0;
}