﻿// Jarvis's preparing code
#define DAILY_IO "3-9-2021"
#define TASKS_IO ""
// #define TIMES_CAL
// <---------------------------------------------------------------->
#ifndef Prepare
////////
#ifndef Preprocessor
#define _CRT_SECURE_NO_WARNINGS
#define enl "\n"
#define uLL unsigned long long int
#define LL  long long int
#define IO_PRE std::cin.tie(0)->sync_with_stdio(0);
#define PT    printf
#define SC(a) scanf("%d",&a);
#define FOR(i, a, b) for (int i = a; i <= b; ++i)
#define FOD(i, a, b) for (int i = a; i >= b; --i)
#define pb  push_back
#define eb  emplace_back
#define mp  make_pair
#define Fi first
#define Se second
#define Pii pair<int, int>
#define Pll pair<long long int, long long int>
#define MOD   1000000007
#define oo    1000111000
#define ooINT 2147483647           //2e31-1 
#define ooULL 18446744073709551615 //2e64-1 || (LL)1e18 + 6886
#define uInt 2e32-1
#endif
////////
#include <iostream>
#include <string>
#include <iterator>
#include <fstream>
#include <vector>
#include <time.h>
#include <algorithm>
#include <stdio.h>
#include <sstream>
#include <string.h>
#include <queue>
#include <stack>
#include <random>
#include <set>
#include <iomanip>
#include <map>
#include <math.h>
#include <limits>
#include <climits>
#include <bitset>
////////
using namespace std;
////////
void Input_Preparing() {}
////////
#endif
// <---------------------------------------------------------------->

void Solver()
{
      int n;
      cin >> n;

      vector<LL>X(n + 1), Y = X;
      FOR(i, 1, n)
      {
            cin >> X[i] >> Y[i];
      }

      sort(X.begin() + 1, X.end());
      sort(Y.begin() + 1, Y.end());

      if(0)
      FOR(i, 1, n)
            cout << X[i] << " " << Y[i] << enl;

      LL First = (X[(X.size() + 1) / 2] - X[(X.size()) / 2]) + 1;
      //cout << " ";
      LL Second = (Y[(Y.size() + 1) / 2] - Y[(Y.size()) / 2]) + 1;

      cout << First * Second << enl;
}

void Processing()
{

      int t;
      cin >> t;
      while (t--)
            Solver();
      
}

////////
int main()
{
#ifdef TIMES_CAL
      clock_t tStart = clock();
#endif
      ////////
      IO_PRE;
#ifndef ONLINE_JUDGE
      freopen(DAILY_IO".INP", "r", stdin);
      freopen(DAILY_IO".OUT", "w", stdout);
#endif
      Processing();
      ////////
#ifdef TIMES_CAL
      printf("\nTime taken: %.3fs", (((double)clock() - tStart) / CLOCKS_PER_SEC));
#endif
      ////////
      return 0;
}