#include<bits/stdc++.h>
using namespace std;
#define fs first
#define sc second
#define MAX 100000
#define pb push_back
#define mp make_pair
#define INF (1LL<<62)
#define MOD 1000000007
typedef long long Int;
typedef pair<Int,Int> pii;
typedef vector<Int> vi;
typedef vector<pii> vii;
Int q,n;
pii P[20];
int main()
{
    cin>>q;
    while (q--)
    {
        cin>>n;
        for (Int i=0;i<n;++i)
            cin>>P[i].fs>>P[i].sc;
        Int maxx=-INF,minx=INF;
        Int maxy=-INF,miny=INF;
        for (Int i=0;i<n;++i)
        {
            maxx=max(P[i].fs,maxx);
            minx=min(minx,P[i].fs);
            miny=min(miny,P[i].sc);
            maxy=max(P[i].sc,maxy);
        }
        bool flag=1;
        for (Int i=0;i<n;++i)
        {
            if (P[i].fs==maxx||P[i].fs==minx||P[i].sc==miny||P[i].sc==maxy)
                continue;
            flag=0;
        }
        if (flag)
            cout<<"YES\n";
        else
            cout<<"NO\n";
    }
    return 0;
}