#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define fi first
#define se second
int n;
void solve(){
    cin >> n;
    map<int,int>mp;
    for(int i=1; i<=n ;i++){
        int x,y;cin >> x >> y;
        mp[-(x+y)]++;
    }
    while(!mp.empty()){
        auto it=mp.begin();
        if(it->fi>=0) break;
        if(it->se<=1){
            mp.erase(it);
            continue;
        }
        mp[it->fi+1]+=it->se/2;
        mp.erase(it);
    }
    if(mp[0]>=3){
        cout <<"NO\n";
    }
    else{
        cout << "YES\n";
    }
}
int main(){
    ios::sync_with_stdio(false);cin.tie(0);
    int t;cin >> t;while(t--) solve();
}