Main.java

import java.util.ArrayList;
import java.util.Scanner;

class Pair {
    int x, y;

    Pair(int a, int b) {
        this.x = a;
        this.y = b;
    }
}

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        ArrayList<Pair> arr = new ArrayList<>();
        for(int i = 0; i < n; i++) {
            Pair p = new Pair(sc.nextInt(), sc.nextInt());
            arr.add(p);
        }
        arr.sort((a, b) -> {
            if(a.y != b.y)
                return a.y - b.y;
            return a.x - b.x;
        });

        for(int i = 0; i < n; i++)
            System.out.println(arr.get(i).x + " " + arr.get(i).y);
    }
}