# include <bits/stdc++.h>

using namespace std;

#define pii pair<int, int>
#define pll pair<ll, ll>

#define pb push_back
#define eb emplace_back
#define mp make_pair

#define fi first
#define se second

#define y0 asjdlksajldjals
#define y1 ajsldjalksdkjlk

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;

const int inf = (int)1e9 + 7;
const int maxn = (int)6e5 + 7;
const int lmaxn = (int)6e6 + 7;
const ll linf = (ll)1e16 + 7;

const ld eps = ld(1e-11);

const ll dx[] = {-1, 0, 0, 1};
const ll dy[] = {0, -1, 1, 0};

ll gcd(ll a, ll b){
    while(b) a %= b, swap(a, b);
    return a | b;
}

ll lcm(ll a, ll b){
    return a * b / gcd(a, b);
}

ll t, n;

int main(){
    scanf("%lld", &t);
    while(t--){
        scanf("%lld", &n);
        vector < pll > a;
        vector < ll > x, y;
        a.resize(n + 1);

        for(ll i = 1; i <= n; ++i){
            scanf("%lld %lld", &a[i].fi, &a[i].se);
            x.pb(a[i].fi);
            y.pb(a[i].se);
        }
        sort(x.begin(), x.end());
        sort(y.begin(), y.end());
        ll ok = 1;
        for(ll i = 1; i <= n; ++i){
            ok &= ((a[i].fi == x[0] || a[i].fi == x[n - 1]) && (a[i].se == y[0] || a[i].se == y[n - 1]));
        }
        printf(ok ? "YES\n" : "NO\n");
    }
    return 0;
}