#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <ctype.h>
#include <deque>
#include <queue>
#include <cstring>
#include <set>
#include <list>
#include <map>
#include <random>
#include <unordered_map>
#include <stdio.h>

using namespace std;

typedef long long ll;
typedef std::vector<int> vi;
typedef std::vector<bool> vb;
typedef std::vector<string> vs;
typedef std::vector<double> vd;
typedef std::vector<long long> vll;
typedef std::vector<std::vector<int> > vvi;
typedef vector<vvi> vvvi;
typedef vector<vll> vvll;
typedef std::vector<std::pair<int, int> > vpi;
typedef vector<vpi> vvpi;
typedef std::pair<int, int> pi;
typedef std::pair<ll, ll> pll;
typedef std::vector<pll> vpll;

const long long mod = 1000000007;

#define all(c) (c).begin(),(c).end()
#define sz(c) (int)(c).size()
#define forn(i, a, b) for(int i = a; i < b; i++)

#define pb push_back
#define mp make_pair

int main()
{

    int q;
    cin>>q;
    forn(i,0,q) {
        int n;
        cin>>n;
        vi x(n);
        vi y(n);
        forn(i,0,n) cin>>x[i]>>y[i];
        vi x2=x;
        vi y2=y;
        x2.pb(-10000);
        x2.pb(10000);
        y2.pb(-10000);
        y2.pb(10000);
        bool ans = false;
        sort(all(y2));
                sort(all(x2));
        forn(i1,0,n+2) {
            forn(i2,i1+1,n+2) {
                forn(j1,0,n+2) {
                    forn(j2,j1+1,n+2) {
                        bool f = true;
                        forn(i,0,n) {
                            bool cur = false;
                            if(x[i] == x2[i1] && (y[i] >= y2[j1] && y[i] <=y2[j2])) cur = true;
                            if(x[i] == x2[i2] && (y[i] >= y2[j1] && y[i] <=y2[j2])) cur = true;
                            
                            if(y[i] == y2[j1] && (x[i] >= x2[i1] && x[i] <=x2[i2])) cur = true;
                            if(y[i] == y2[j2] && (x[i] >= x2[i1] && x[i] <=x2[i2])) cur = true;
                            f = f&&cur;
                        }
                        if(f) ans = true;
                    }
                }
            }
        }
        if(ans) printf("YES\n");
        else printf("NO\n");
    }
    
}