import java.io.File;
import java.io.FileReader;
import java.io.BufferedReader;
import java.io.IOException;
import java.util.LinkedList;
import java.util.HashSet;
import java.util.TreeSet;

class Main2 {

    private static TreeSet<Tort> loadTort(String filename) {
        try {
            TreeSet<Tort> result = new TreeSet<Tort>();
            BufferedReader reader = new BufferedReader(new FileReader(new File(filename)));
            
            for( String line = reader.readLine(); line != null; line = reader.readLine() ) {
                String[] splitted = line.split(" ");
                result.add(new Tort(Integer.parseInt(splitted[0]), Integer.parseInt(splitted[1])));
            }
            
            return result;
        } catch( IOException e ) { return null; }
    }
    
    private static void printTort(TreeSet<Tort> tortek) {
        for( Tort t : tortek )
            System.out.println(t);
    }

    public static void main(String[] args) {
        printTort(loadTort("input.txt"));
    }
}