#include <vector>
#include<queue>
#include<limits.h>
#include <list>
#include <map>
#include<unordered_map>
#include <set>
#include<unordered_set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include<cmath>
#include<memory.h>
#include<assert.h>
#include<tuple>
#include<fstream>

using namespace std;

#define ff first
#define ss second
#define all(data) data.begin(),data.end()
#define mp(a,b) make_pair(a,b)
#define mt make_tuple

#define sig cout << "reached" << endl;
#define parr(data) {for(int it = 0; it < data.size(); it++) cout << data[it] << " "; cout << endl;}

#define forr(i,s,e) for(int i=s;i<e;i++)
#define forre(i,s,e) for(int i = s - 1;i>=e;i--)

#define sd(x) scanf("%d",&x);
#define slld(x) scanf("%lld",&x);
#define sf(x) scanf("%Lf",&x);
#define sc(x) scanf(" %c",&x);

#define pd(x) printf("%d\n",x);
#define pd_(x) printf("%d ",x);
#define plld(x) printf("%lld\n",x);
#define nl printf("\n");

typedef unsigned long long int llu;
typedef long long int ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

int inf = 1000000005;
ll llinf = 4000000000000000005LL;
ll mod = 1000000007;
double pi = 3.1415926535897;
int dx[] = { 1, 1, -1, -1 };
int dy[] = { 1, -1, 1, -1 };

typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<bool> vb;
typedef vector<vb> vvb;
typedef vector<pii> vpi;
typedef vector<pll> vpl;
typedef vector<vpi> vvpi;
typedef vector<vpl> vvpl;
typedef vector<char> vc;

vb isprime; vi primes;
void seive(int n, bool wantlist = true){ isprime.resize(n + 1, true); isprime[0] = isprime[1] = false; int sq = sqrt(n + 1); forr(i, 2, sq + 1){ if (isprime[i]){ for (int j = i*i; j <= n; j += i) isprime[j] = false; } } for (int i = 2; wantlist && i <= n; i++){ if (isprime[i]) primes.push_back(i); } }
template<class T>
inline T gcd(T a, T b){	while (b > 0){ a %= b; swap(a, b); } return a; }
template<class T>
inline T lcm(T a, T b){ return a*b / gcd(a, b); }
template<class T>
inline vector<T> operator+(vector<T>& a, vector<T>& b) {assert(a.size() == b.size()); int n = a.size(); vector<T> c(n); for(int i = 0; i < n; i++) c[i] = a[i] + b[i]; return c; }
inline ll bexp(ll x, ll n){ ll res = 1; x %= mod; while (n){ if (n & 1) res = res * x % mod; x = x * x % mod; n >>= 1; } return res; }
inline bool ispalin(string& str){ int n = str.length(); for(int i = 0; i < n / 2; i++) if(str[i] != str[n - i - 1]) return false; return true; }

//***********************************************************************************

int main(){
	///freopen("i.in", "r", stdin);
	int q; sd(q);
	while(q--){
		int n; sd(n);
		vi x(n), y(n);
		forr(i, 0, n){ sd(x[i]); sd(y[i]); }
		int u = *max_element(all(y)), d = *min_element(all(y)), l = *min_element(all(x)), r = *max_element(all(x));
        bool ans = true;
		//if(u == d || l == r) ans = false;
		for(int i = 0; i < n && ans; i++){
			if((x[i] != l && x[i] != r) && (y[i] != u && y[i] != d)) ans = false;
		}
        if(ans) cout << "YES" << endl;
        else cout << "NO" <<endl;
	}
}