#include <bits/stdc++.h>

using namespace std;

#define vec vector
#define ALL(x) (x).begin(), (x).end()
#define mp make_pair
#define mt make_tuple

typedef pair< int, int > pii;
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

int const inf = 1000 * 1000 * 1000;
ll const inf64 = 1ll * inf * inf;

bool solve() {

    int n;
    scanf("%d", &n);

    vec< pii > crd(n);
    for(int i = 0;i < n;i++) {
        scanf("%d %d", &crd[i].first, &crd[i].second);
    }

    sort(ALL(crd));
    crd.resize(n = unique(ALL(crd)) - crd.begin());

    if(n == 1) {
        printf("YES\n");
        return true;
    }

    vec< int > x(n);
    vec< int > y(n);

    for(int i = 0;i < n;i++) {
        x[i] = crd[i].first;
        y[i] = crd[i].second;
    }

    int min_x = *min_element(ALL(x));
    int max_x = *max_element(ALL(x));
    int min_y = *min_element(ALL(y));
    int max_y = *max_element(ALL(y));

    if(min_x == max_x && min_y == max_y) {
        printf("NO\n");
        return true;
    }

    for(int i = 0;i < n;i++) {
        if(min_x == x[i] || max_x == x[i]) continue;
        if(min_y == y[i] || max_y == y[i]) continue;
        printf("NO\n");
        return true;
    }

    printf("YES\n");

    return true;
}

int main() {

    int q;
    scanf("%d", &q);

    for(int iter = 0;iter < q;iter++) {
        solve();
    }

    return 0;
}