#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 */   
    int q,n,x[11],y[11];
    cin>>q;
    while(q--){
        cin>>n;
        for(int i=0;i<n;i++)
            cin>>x[i]>>y[i];
        if(n<=3) {cout<<"YES"<<endl;continue;}
        cout<<"NO"<<endl;
    }
    return 0;
}