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


int main() {
    
    int q;
    cin >> q;
    while (q--){
        unordered_map<int, int> xCount, yCount;
        int n, x, y;
        cin >> n;
        for (int i = 0; i < n; i++){
            cin >> x >> y;
            xCount[x]++;
            yCount[y]++;
        }
        if (xCount.size() <= 2 && yCount.size() <=2){
            cout << "YES";
        }
        else {
            cout << "NO";
        }
        cout << endl;
    }
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}