/*
 * Avinash Gurjar(algebra1415011), Nit Silchar
*/
#include<bits/stdc++.h>
#define ll  long long int
using namespace std;
#define loop(i,start,end) for (ll i=start;i<=end;i++)
#define pool(i,start,end) for(ll i=start;i>=end;i--)
#define algebra() ll t;scanf("%lld",&t);while(t--)
#define vt(v) vector <ll> v;
#define pb(n) push_back(n);`
#define m_p(a,b) make_pair(a,b)
#define fill(a,value) memset(a,value,sizeof(a));
#define vtp(vp) vector <pair <ll,ll> > vp;
#define sci(n) scanf("%lld",&n);
#define scii(x,y) scanf("%lld%lld", &x,&y);
#define sciii(x,y,z) scanf("%lld%lld%lld", &x, &y, &z);
#define scs(s) cin>>s;
#define pr(n) printf("%lld",n);
#define pnt() printf("hope");
#define gp() printf(" ");
#define ln() printf("\n"); 
#define MOD 1000000007
#define PI  3.14159265358979323846
#define MAX_INT (ll)0x7fffffff
#define MIN_INT (ll)0x80000000
#define MAX 1000008
#define debug() cout<<"######"<<endl
 
ll gcd(ll a,ll b)
{
    if(b==0)
        return a;
    else
        return gcd(b,a%b);
}
 
ll modex(ll a,ll b,ll c)
{
    ll ans=1;
    while(b)
    {
        if(b&1)
            ans=(ans*a)%c;
        a=(a*a)%c;
        b /=2;
    }
    return ans;
 
}
 

int main() {
    ll qt;
    cin>>qt;
    while(qt--)
        {
      ll nn;
        cin>>nn;
        ll arr[nn][2];
        for(ll i=0;i<nn;i++)
            cin>>arr[i][0]>>arr[i][1];
       ll x_min=INT_MAX,y_min=INT_MAX,x_max=INT_MIN,y_max=INT_MIN;
        for(ll i=0;i<nn;i++)
            {
            x_min=min(x_min,arr[i][0]);
            y_min=min(y_min,arr[i][1]);
            x_max=max(x_max,arr[i][0]);
            y_max=max(y_max,arr[i][1]);
        }
       ll flag=1;
        for(ll i=0;i<nn;i++)
            {
            ll xx=arr[i][0];
            ll yy=arr[i][1];
            if(xx+0*yy==x_min || xx+0*yy==x_max || yy+0*xx==y_min || yy+0*xx==y_max )
                flag=1;
            else
                flag=0;
            if(flag==0)
                break;
                
        }
        if(flag==0)
            cout<<"NO"<<endl;
        else
            cout<<"YES"<<endl;
    }
}