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


int main() {
    ios_base::sync_with_stdio(false);cin.tie(0);
    int q;
    cin>>q;
    while(q--)
        {
        int n;
        cin>>n;
        int a[n],b[n];
        long c=0;
        cin>>a[0]>>b[0];
        int maxa = abs(a[0]);
        int maxb = abs(b[0]);
        for(int i=1;i<n;i++)
            {
            cin>>a[i]>>b[i];
            if(maxa<abs(a[i]))
                maxa = a[i];
            if(maxb<abs(b[i]))
                maxb = b[i];
                  }
        for(int i=0;i<n;i++)
            {
            if((a[i]==0&&abs((b[i])<=maxb))||(b[i]==0)&&(abs(a[i])<=maxa)||(abs(a[i])==maxa||abs(b[i])==maxb))
                c = c+1;
        }
        if(c==n)
        cout<<"YES"<<endl;
        else
        cout<<"NO"<<endl;
    }
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}