import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        Scanner in = new Scanner (System.in);
        int N = in.nextInt();
        
        for(int i=0; i<N; i++){
            int size = in.nextInt();
            HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();
            
            for(int s=0; s<size*2; s++){
                int nextInt = in.nextInt();
                map.put(new Integer(nextInt), new Integer(1));
            }
            
            if(map.size()>2){
                System.out.println("NO");
            } else {
                System.out.println("YES");
            }
        }
        
    }
}