#include <bits/stdc++.h>
using namespace std;

using ll=long long;
//#define int ll
#define rep(i,a,b) for(int i=a;i<(b);i++)
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
using pii=pair<int,int>;
using vi=vector<int>;
#define fi first
#define se second
#define pb push_back

vector<int> ones;
const int N = 2e9+100;
const int M = N - 50;
unordered_map<int, int> a;

//int a[N];
//int b[N];

void add(int m)
{
    a[m]++;
    ones.pb(m);
    while (a[m] > 1) {
        a[m] -= 2;
        a[m + 1]++;
        //ones.pb(m + 1);
        m++;
    }
}

void solve()
{
    //ones.clear();
    a.clear();
    int n;
    cin>>n;
    for (int i=0; i<n; i++)
    {
        int x, y;
        cin>>x>>y;
        add(M-x-y);
    }
    add(M);

    int mx = -1;
    for (auto [x, y] : a)
        if (y > 0)
            mx = max(mx, x);
    if (mx < M+2)
        cout<<"YES\n";
    else
        cout<<"NO\n";


    for (int i : ones)
        a[i] = 0;
}

signed main() {
    cin.tie(0)->sync_with_stdio(0);
    cin.exceptions(cin.failbit);
    a.reserve(2e6);
    int t;
    cin>>t;
//    b[M] = b[M+1] = 1;
    for (int i=0; i<t; i++)
        solve();
}