#include <iostream.h>
#include <apvector.h>
#include <fstream.h>

void quickSort (apvector<int> &list, int first, int last);

struct item

{

      int id;

      int inv;

};

  

struct storeType

{

      apvector<item> list;

      int number;

};

ostream &  operator<< (ostream & Out, const infoType &temp)

{

        Out << temp.id << "     " << temp.inv << endl;

        return Out;

}

int main (void) {
	storeType inventory;
	ifstream infile ("file50.txt",ios::in);
	int n = 0;
	infile >> n;
	inventory.list.size(n);
	inventory.number = n;
	apvector<int> list(n);
	for (int g = 0;g < n;g++) {
		int y,z;
		infile >> y;infile >> z;
		inventory.list[g].id = y;
		inventory.list[g].inv = z;
		list[g]=y;
	}
	quickSort(list,0,n-1);
	return 0;
}

void quickSort (apvector<int> &list, int first, int last) 

                            { 


                                   int g = first, h = last; 

                                   int midIndex, dividingValue, temp; 

                             

                                   midIndex = (first + last) / 2; 

                                   dividingValue = list[midIndex]; 

                                   do 

                                   { 

                                           while (list[g] < dividingValue) g++; 

                                           while (list[h] > dividingValue) h--; 

                                           if (g <= h) 

                                           { 

                                                   swap(list[g], list[h]); 

                                                   g++; 

                                                   h--; 

                                           } 

                                   } 

                                   while (g < h); 

                                   if (h > first) quickSort (list,first,h); 

                                   if (g < last) quickSort (list,g,last); 

                           }