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


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */  
    long long int t,i,n,flag=0;
    cin>>t;
    while(t--){
        flag=0;
        cin>>n;
        vector<int>arr(2*n);
        cin>>arr[0]>>arr[1];
        for(i=2;i<(n*2);i+=2){
            cin>>arr[i]>>arr[i+1];
            if(!(arr[i]!=arr[i-2]) && (arr[i+1]!=arr[i-1]))
             {                
                    flag=1;
                    break;
             }
        }
        if(flag==1)
            cout<<"YES"<<endl;
        else
            cout<<"NO"<<endl;
        flag=0;
    }
    return 0;
}