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.util.ArrayList;
import java.util.Collections;
import java.util.Scanner;
public class Main {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		int N=0,M=0;
        int[] Pi,Yi;
        String[] ID;
        String plpd;
        String xlpd;
        Scanner sc = new Scanner(System.in);
        N=sc.nextInt();
        M=sc.nextInt();
        Pi = new int[M+1];
        Yi = new int[M+1];
        ID = new String[M+1];
        for(int index=1;index<=M;index++){
        	Pi[index]=sc.nextInt();
        	Yi[index]=sc.nextInt();
        }
        
        for(int i=1;i<=M;i++){
        	ArrayList<Integer> arr=new ArrayList<Integer>();
        	plpd="";
        	xlpd="";
        	for(int j=1;j<=M;j++){
        		if(Pi[i]==Pi[j]){
        			arr.add(Yi[j]);
        		}
        	}
        	Collections.sort(arr);
        	for(int k=0;k<6-Integer.toString(Pi[i]).length();k++){
        		plpd += "0";
        	}
        	for(int k=0;k<6-Integer.toString(arr.indexOf(Yi[i])+1).length();k++){
        		xlpd += "0";
        	}
        	ID[i]=plpd.toString()+Pi[i]+xlpd.toString()+(arr.indexOf(Yi[i])+1);
        }
       for(int i=1;i<=M;i++){
    	   System.out.println(ID[i].toString());
       }
	}
}