text: #include<bits/stdc++.h>
  using namespace std;
  
  int main()
  {
  
  	vector<int> v = {2,5,1,6,2,8,10};
  	for(auto it = v.begin(); it!=v.end();it++)
  	{
  		cout<<(*it)<<" ";
  	}
  
  	cout<<endl;
  
  	int N;cin>>N;
  	vector<pair<int,int>> v_p;
  	for(auto i=0;i<N;i++)
  	{	
  		int n;cin>>n;
  		for(auto j=0;j<n;j++)
  		{
  			int x,y;cin>>x>>y;
  			v_p.push_back({x,y});
  		}
  	}
  
  	for(auto it=v_p.begin();it!=v_p.end();it++)
  		cout<<(it->first)<<" "<<(it->second)<<"\n";
  	return 0;
  }
  