Problem:
Sorting Pairs

Write a program which print coordinates $(x_i, y_i)$ of given $n$ points on the plane by the following criteria.

first by $x$-coordinate

in case of a tie, by $y$-coordinate

Input

The input is given in the following format.

$n$
$x_0 \; y_0$
$x_1 \; y_1$
:
$x_{n-1} \; y_{n-1}$

In the first line, the number of points $n$ is given. In the following $n$ lines, coordinates of each point are given.

Output

Print coordinate of given points in order.

Constraints

$1 \leq n \leq 100,000$

$-1,000,000,000 \leq x_i, y_i \leq 1,000,000,000$

Sample Input 1

5
4 7
5 5
2 3
6 8
2 1

Sample Output 1

2 1
2 3
4 7
5 5
6 8

Solution in C++ (judge verdict: Accepted)

#include<iostream>
#include<algorithm>
using namespace std;

struct object{
    int x,y;

    bool operator < (const object &o) const {
        if(x != o.x){
            return x < o.x;
        }
        else {
            return y < o.y;
        }
    }
};

int main(void){
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    int n;
    cin >> n;
    object o[n];
    
    for(int i = 0;i < n;++i){
        cin >> o[i].x >> o[i].y;
    }

    sort(o,o + n);

    for(int i = 0;i < n;++i){
        cout << o[i].x << " " << o[i].y << endl;
    }
}