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


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