#include <bits/stdc++.h>
using namespace std;
bool on_border(int x1, int y1, int x2, int y2, int x, int y){
    if(x1 > x2)
        swap(x1,x2);
    if(y1 > y2)
        swap(y1,y2);
    if(x == x1 && y1 <= y && y <= y2)
        return true;
    if(x == x2 && y1 <= y && y <= y2)
        return true;
    if(y == y1 && x1 <= x && x <= x2)
        return true;
    if(y == y2 && x1 <= x && x <= x2)
        return true;
    return false;
}
string solve(){
    int n;
    cin >> n;
    vector<pair<int,int> > arr(n);
    vector<int> x,y;
    for(int i = 0; i < n; ++i){
        cin >> arr[i].first >> arr[i].second;
        x.push_back(arr[i].first);
        y.push_back(arr[i].second);
    }
    for(int x1 : x)
        for(int x2 : x)
            for(int y1 : y)
                for(int y2 : y){
                    bool ok = true;
                    for(auto t : arr)
                        if(!on_border(x1,y1,x2,y2,t.first,t.second))
                            ok = false;
                    if(ok)
                        return "YES";
                }
    return "NO";
} 
int main(){
    int q;
    cin >> q;
    while(q--)
        cout << solve() << '\n';
}