/*
*
*"@NainwalArun"
*
*/
#include <bits/stdc++.h>
using namespace std ;

#define ft first
#define sd second
#define pb push_back
#define all(x) x.begin(),x.end()

#define ull unsigned long long int
#define ll long long int
#define vi vector<long long int>
#define vii vector<pair<long long int,long long int> >
#define pii pair<long long int,long long int>
#define mp make_pair
#define arun() int main()
#define loop(i, a, b) for(i=a; i<b; i++)
#define pool(i, a, b) for(i=a; i>b; i--)
const int N = 1e5 + 10;
const int mod = 1e9 + 7;
const ll INF = 1LL << 62;

ll power(ll x,ll y){
  ll t=1;
  while(y>0){
    if(y%2) y-=1,t=t*x%mod;
    else y/=2,x=x*x%mod;
  }
  return t;
}

ll inverse(ll q)
{
    ll t;
    t=power(q,mod-2);
    return t;
}


ll factors(ll n)
{
	ll cou=0,i,k=1,k1;
    for( i=2;i<=sqrt(n);i++){
        if(n%i==0){
            k1=0;
            while(n%i==0){
            	n=n/i;
            	k1++;
            }
            k=k*(k1+1);
        }
    }
    if(n!=1){
    	k=k*2;
    }
    return k;
}

ll fact(ll n){
    ll facti[100001];
    facti[0]=1;
    facti[1]=1;
    for(ll i=2;i<100001;i++){
        facti[i]=(facti[i-1]*i)%mod;
    }
    return facti[n];
}

ll gcd (ll a, ll b)
{
    ll c;

    if ( b == 0 )
        return a;

    else
        while ( b != 0 )
        {
            c = b;
            b = a % b;
            a = c;
        }

        return a;
}

bool cmp(pair<ll,ll>p1,pair<ll,ll>p2){
    if(p1.ft>p2.ft){
        return true;
    }
    else if(p1.ft==p2.ft){
        if(p1.sd<=p2.sd){
            return true;
        }
        else{
            return false;
        }
    }
    else{
        return false;
    }
}

ll prime[1000001]={0};

arun(){
    /*ll i,j,k,l;
    prime[0]=1;
    prime[1]=1;
    for(i=0;i<=sqrt(1000001);i++){
        if(prime[i]==0){
            for(j=2*i;j<1000001;j=j+i){
                prime[j]=1;
            }
        }
    }
    vector<ll>primes;
    for(i=0;i<1000001;i++){
        if(prime[i]==0){
            primes.pb(i);
        }
    }*/
    ll q,n,i,j,k,l,x,y,x1,y1;
    cin>>q;
    loop(k,0,q){
        cin>>n;
        ll a[n],b[n];
        x=INT_MAX;
        x1=INT_MIN;
        y=INT_MIN;
        y1=INT_MAX;
        loop(i,0,n){
            cin>>a[i]>>b[i];
            y=max(y,b[i]);
            y1=min(y1,b[i]);
            x=min(x,a[i]);
            x1=max(x1,a[i]);
        }
        ll ans=0;
        loop(i,0,n){
            if(a[i]==x1 || a[i]==x || b[i]==y || b[i]==y1){
                ans++;
            }
        }
        if(ans==n){
            cout<<"YES"<<endl;
        }
        else{
            cout<<"NO"<<endl;
        }
    }
return 0;

}