#include <iostream>
#include <iomanip>
#include <stdio.h>
#include <set>
#include <vector>
#include <map>
#include <cmath>
#include <algorithm>
#include <memory.h>
#include <string>
#include <sstream>
#include <cstdlib>
#include <ctime>
#include <cassert>

using namespace std;

typedef long long LL;
typedef pair<int,int> PII;

#define MP make_pair
#define PB push_back
#define FF first
#define SS second

#define FORN(i, n) for (int i = 0; i <  (int)(n); i++)
#define FOR1(i, n) for (int i = 1; i <= (int)(n); i++)
#define FORD(i, n) for (int i = (int)(n) - 1; i >= 0; i--)

#define DEBUG(X) { cout << #X << " = " << (X) << endl; }
#define PR0(A,n) { cout << #A << " = "; FORN(_,n) cout << A[_] << ' '; cout << endl; }

#define MOD 1000000007
#define INF 2000000000

int GLL(LL& x) {
    return scanf("%lld", &x);
}

int GI(int& x) {
    return scanf("%d", &x);
}

int q, n, x, y;

vector<PII> pts;

int main() {
    GI(q);

    while (q--) {
        GI(n);

        int minx = INF, maxx = -INF;
        int miny = INF, maxy = -INF;

        vector<PII> pts;

        while (n--) {
            GI(x); GI(y); pts.PB(MP(x, y));
            minx = min(minx, x);
            maxx = max(maxx, x);
            miny = min(miny, y);
            maxy = max(maxy, y);
        }

        bool ok = true;

        for (auto p : pts) {
            if (p.FF == minx || p.FF == maxx || p.SS == miny || p.SS == maxy) {
                continue;
            }
            else {
                ok = false;
            }
        }

        if (ok) {
            printf("YES\n");
        }
        else {
            printf("NO\n");
        }
    }
    
    return 0;
}