#include <iostream>
#include <utility>
#include <vector>

using namespace std;


void solve() {
    int num;
    cin >> num;

    vector<pair<int, int>> p;
    for (int i = 0; i < num; i++) {
        int first, second;
        cin >> first >> second;
        p.push_back(make_pair(first, second));
    }

    int max_size = 0;
    pair<int, int> last_minmax;
    vector<pair<int, int>> w;
    for (int i = 0; i < p.size(); i++) {
        int max_low = p.front().first;
        int min_high = p.front().second;
        int last_min = 0;
        int last_max = 0;
        int last_pos = 0;
        for (int j = i; j < p.size(); j++) {
            if (p.at(j).first >= last_max || p.at(j).second <= last_min) {
                max_low = p.at(j).first;
                min_high = p.at(j).second;
                last_pos = j - i;
            }
            else {
                if (p.at(j).first > max_low)
                    max_low = p.at(j).first;
                if (p.at(j).second < min_high)
                    min_high = p.at(j).second;
            }


            w.push_back(p.at(j));
            last_min = p.at(j).first;
            last_max = p.at(j).second;
            auto size = (min_high - max_low) * (w.size() - last_pos);
            if (size > max_size)
                max_size = size;
            //for (auto k : w)
            //cout << k.first << " - " << k.second << " ";
            //cout <<" size = "<< size << endl;
            //if (j == p.size() - 1)
            //  w.clear();
        }
        w.clear();
    }
    cout << max_size << endl;
}



int main() {

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