#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
int main() 
{
    int q;
    cin>>q;
    for(int i = 0; i<q; i++)
    {
        int n;
        cin>>n;
        double a[100][2];
        for(int j = 0; j<n; j++)
            cin>>a[j][0]>>a[j][1];
        int found = 0;
        if(n == 1 || n == 2)
            found = 1;
        if(n == 3)
        {
            if(a[0][0] == a[1][0] && a[0][0] == a[2][0])
                found = 1;
            if(a[0][1] == a[1][1] && a[1][1] == a[2][1])
                found = 1;
            if(a[0][0] == a[1][0] && a[0][1] == a[2][1])
                found = 1;
            if(a[1][0] == a[0][0] && a[1][1] == a[2][1])
                found = 1;
            if(a[2][0] == a[1][0] && a[2][1] == a[0][1])
                found = 1;
            if(a[0][1] == a[1][1] && a[0][0] == a[2][0])
                found = 1;
            if(a[1][1] == a[0][1] && a[1][0] == a[2][0])
                found = 1;
            if(a[2][1] == a[1][1] && a[2][0] == a[0][0])
                found = 1;
        }
        if(n>=4)
        {
            for(int z = 0; z<n; z++)
            {
                for(int c = z+1; c<n; c++)
                {
                    for(int v = c+1; v<n; v++)
                    {
                        for(int g = v+1; g<n; g++)
                        {
                            if(a[z][0] == a[c][0] && a[v][0] == a[g][0])
                                found = 1;
                            if(a[z][0] == a[v][0] && a[c][0] == a[g][0])
                                found = 1;
                            if(a[z][0] == a[g][0] && a[c][0] == a[v][0])
                                found = 1;
                            if(a[z][1] == a[c][1] && a[v][1] == a[g][1])
                                found = 1;
                            if(a[z][1] == a[v][1] && a[c][1] == a[g][1])
                                found = 1;
                            if(a[z][1] == a[g][1] && a[c][1] == a[v][1])
                                found = 1;
                        }
                        if(found == 1)
                            break;
                    }
                    if(found == 1)
                        break;
                }
                if(found == 1)
                    break;
            }
        }
        if(found == 1)
            cout<<"YES"<<endl;
        else
            cout<<"NO"<<endl;
    }
    return 0;
}