Problem:
Score: 300 points

Problem Statement

In Republic of Atcoder, there are N prefectures, and a total of M cities that belong to those prefectures.

City i is established in year Y_i and belongs to Prefecture P_i.

You can assume that there are no multiple cities that are established in the same year.

It is decided to allocate a 12-digit ID number to each city.

If City i is the x-th established city among the cities that belong to Prefecture i, the first six digits of the ID number of City i is P_i, and the last six digits of the ID number is x.

Here, if P_i or x (or both) has less than six digits, zeros are added to the left until it has six digits.

Find the ID numbers for all the cities.

Note that there can be a prefecture with no cities.

Constraints

1 \leq N \leq 10^5

1 \leq M \leq 10^5

1 \leq P_i \leq N

1 \leq Y_i \leq 10^9

Y_i are all different.

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N M
P_1 Y_1
:
P_M Y_M

Output

Print the ID numbers for all the cities, in ascending order of indices (City 1, City 2, ...).

Sample Input 1

2 3
1 32
2 63
1 12

Sample Output 1

000001000002
000002000001
000001000001

As City 1 is the second established city among the cities that belong to Prefecture 1, its ID number is 000001000002.

As City 2 is the first established city among the cities that belong to Prefecture 2, its ID number is 000002000001.

As City 3 is the first established city among the cities that belong to Prefecture 1, its ID number is 000001000001.

Sample Input 2

2 3
2 55
2 77
2 99

Sample Output 2

000002000001
000002000002
000002000003

Solution in Java8 (OpenJDK 1.8.0) (judge verdict: Time Limit Exceeded)

import java.io.FileInputStream;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;

public class Main {

    static int N;
    static int M;
    static int [][] city;
    static String [] soultion;
    public static void main(String args[]) throws Exception {

       
        Scanner sc = new Scanner(System.in);
        
        N= sc.nextInt();
        M= sc.nextInt();

        city = new int[M][2];
        soultion= new String[M];
        for (int i = 0; i < M; i++) {
            for (int j = 0; j < 2; j++) {
                city[i][j] = sc.nextInt();
            }
        }
        for (int k = 1; k <= N; k++) {
            List<Integer> list = new ArrayList<>();
            for (int j = 0; j <M; j++) {
                if (city[j][0] == k){
                    list.add(city[j][1]);
                }
             }
            sort(k,list);
        }
        for (int i = 0; i < soultion.length; i++) {
            System.out.println(soultion[i]);
        }
        
    }

    public static void sort(int n,List<Integer> list){
        Collections.sort(list);
        for (int i = 0; i < list.size(); i++) {
            StringBuilder str=new StringBuilder();
            str = str.append(String.format("%06d", n)).append(String.format("%06d",(i+1)));
                for (int j = 0; j < M; j++) {
                    if (city[j][1] == list.get(i) && city[j][0] == n){
                        soultion[j]=str.toString();
                    }
                }

        }

    }
}