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

void solve(){
    int n;
    cin >> n;
    vector<int64_t> X;
    vector<int64_t> Y;
    int x,y;
    for (int i = 0; i < n; i++){
        cin >> x >> y;
        X.push_back(x);
        Y.push_back(y);
    }
    sort(X.begin(),X.end());        
    sort(Y.begin(),Y.end());        
    int64_t res;
    if (n%2 == 0){
        res = (X.at(n/2)-X.at(n/2-1)+1)*(Y.at(n/2)-Y.at(n/2-1)+1);
    } else {
        res = 1;
    }
    cout << res << endl;
    return;
}

int main() {
    int t;
    cin >> t;
    while (t){
        solve();
        t--;
    }
    return 0;
}