#include <bits/stdc++.h>
using namespace std;
 
bool cmp(pair<int,int> p1,pair<int,int> p2){
	if(p1.first!=p2.first){
		return p1.first<p2.first;
	}
	return p1.second>p2.second;
}
int main() {
	int t;
	scanf("%d",&t);
	while(t--){
	vector<pair<int,int>> v;
	int n;
	scanf("%d",&n);
	for(int i=0;i<n;i++){
		int x,y;
		scanf("%d%d",&x,&y);
		v.push_back(make_pair(x,y));
	}
	sort(v.begin(),v.end(),cmp);
	for(int i=0;i<n;i++){
		printf("%d %d\n",v[i].first,v[i].second);
	}
	}
	return 0;
}

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

MQoKNQoKMyA0CgotMSAyCgo1IC0zCgozIDMKCi0xIC0yCgo=

1

5

3 4

-1 2

5 -3

3 3

-1 -2