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


int main() {
    int i,q,j,n,x,y,count;
    cin>>q;
    for(i=0;i<q;i++)
        {
        cin>>n;
        count=0;
        for(j=0;j<n;j++)
            {
            cin>>x>>y;
            if(x==0&&y==0||x==0&&y==1)
                {
                count++;
            }
            if(x==1&&y==1||x==1&&y==0)
                {
                count++;
            }
        }
        if(count==n)
            {
            cout<<"YES"<<endl;
        }
        else
            {
            cout<<"NO"<<endl;
        }
        }
    
    return 0;
}