#include <bits/stdc++.h>
using namespace std;
#define IO ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
const long long MOD = 1e9 + 7, OO = 1e18;
const double PI = acos(-1);
const int N = 1e6 + 5;
const int dx[4] = {0, 0, 1, -1};
const int dy[4] = {1, -1, 0, 0};

long long t, n;
pair<long long, long long>a[N];

bool cmp(pair<long long, long long>a, pair<long long, long long>b)
{
    //a.first, a.second - b.first, b.second
    if (a.first < b.first)return 1;
    if (a.first > b.first)return 0;
    return a.second > b.second;
}

int main()
{
    IO
    cin >> t;
    while (t--)
    {
        cin >> n;
        for (int i = 1; i <= n; i++)
        {
            cin >> a[i].first >> a[i].second;
        }
        sort(a + 1, a + n + 1, cmp);
        for (int i = 1; i <= n; i++)
        {
            cout << a[i].first << ' ' << a[i].second << '\n';
        }
    }
    return 0;
}