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

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

int main() {
    #ifdef LOCAL
        freopen("Data.inp", "r", stdin);
        freopen("Data.out", "w", stdout);
    #endif

    int TC; cin >> TC;
    while (TC--) {
        int n, x[20], y[20]; cin >> n;
        for (int i = 0; i < n; ++i) cin >> x[i] >> y[i];

        if (*max_element(x, x + n) == *min_element(x, x + n) ||
            *max_element(y, y + n) == *min_element(y, y + n)) {
                puts("YES");
                continue;
            }
        int L = *min_element(x, x + n), R = *max_element(x, x + n);
        int D = *min_element(y, y + n), U = *max_element(y, y + n);
        bool flag = true;
        for (int i = 0; i < n; ++i) {
            if (L < x[i] && x[i] < R && D < y[i] && y[i] < U) {
                flag = false;
                break;
            }
        }
        puts(flag ? "YES" : "NO");
    }

    return 0;
}