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


#define boost ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)

typedef long long ll;
struct point{
    ll x,y;
}
vector<point> vp;
set<ll> sx,sy;

int main() {
     boost;
    ll T,N,i,j,k,M,m,n;
    cin >> T;
    while(T--){
        ll Q;
        vp.clear();
        sx.clear();
        sy.clear();
        cin >> Q;
        for(i = 0 ; i < Q; i++){
            point l;
            cin >> l.x >> l.y;
            vp.push_back(l);
        }
        if(Q == 1 || Q == 2){
            cout << "YES" << endl;
            continue;
        }
        for(i = 0 ; i < vp.size() ; i++)
            sy.insert(vp[i].y);
        for(i = 0 ; i < vp.size() ; i++)
            sx.insert(vp[i].x);
        if(sx.size() <= 2 && sy.size() <= 2)
            cout << "YES" << endl;
        else
            cout << "NO" << endl;
    }
    return 0;
}