#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define ld long double
#define vi vector<int>
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define pii pair<int,int>
#define pll pair<ll,ll>
#define vii vector<pii >
#define vll vector<ll >
#define cps CLOCKS_PER_SEC
#define eb emplace_back
#define rep(i, begin, end) for (__typeof(end) i = (begin) - ((begin) > (end)); i != (end) - ((begin) > (end)); i += 1)
#define all(a) (a).begin(), (a).end()
#define sz(a) int((a).size())
#define print(s) cout<<#s<<" : ";for(auto i:(s))cout<<i<<" ";cout<<"\n";
#define slld(t) scanf("%lld",&(t))
#define sd(t) scanf("%d",&(t))

vi x,y;
inline bool is_on(int x1,int x2,int y1, int y2, int a, int b)
{
    if(x1>x2)
        swap(x1,x2);
    if(y1>y2)
        swap(y1,y2);
    if(a<x1 || a>x2)
        return 0;
    if(b<y1||b>y2)
        return 0;
    if(a==x1 || a==x2 || b==y1 || b==y2)
        return 1;
    return 0;
}
int main()
{
    int n;
    int q;
    sd(q);
    while(q--){
        x.clear();
        y.clear();
        sd(n);
        x.resize(n),y.resize(n);
        rep(i,0,n)
        sd(x[i]),sd(y[i]);
        bool FLAG = 0;
        for(int x1:x)
        for(int x2:x)
        for(int y1:y)
        for(int y2:y)
        {
            if(FLAG)
                break;
            bool flag = 1;
            for(int i = 0;i<n;i++)
                if(!is_on(x1,x2,y1,y2,x[i],y[i]))
                    flag = 0;
            FLAG = flag;    
        }
        cout<< (FLAG?"YES\n":"NO\n");
    }
}