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: Runtime Error)



import java.util.*;

class admin/* implements Comparable<admin>*/{
	
	int index;
	int pref;
	int city;
	
	public admin(int index, int pref, int city){
		this.index = index;
		this.pref = pref;
		this.city=city;
	}
	
	
	
}

class Main {



  public static void main (String[] args) {
    
    Scanner sc = new Scanner(System.in);
    
    int n = sc.nextInt(); //県の数
    int m = sc.nextInt(); //市の数
 
    ArrayList <admin> array= new ArrayList<>();
    ArrayList <String> ans= new ArrayList<>();
     
    int pref=0;
    int city=0;;
    
    
    for(int i=0; i<m;i++){
      pref= sc.nextInt();
      city = sc.nextInt();
      admin A =new admin(i,pref,city);
      array.add(A);
      
      }
    
    sc.close();
    
    
    array.sort((a,b)-> a.city - b.city ); /*ラムダ式*/
    array.sort((a,b)-> a.pref - b.pref ); /*ラムダ式*/
    
    
    
    int tmp = array.get(1).pref;
    int k=1;
    
    for(int i=0; i<m;i++){
    	if(tmp == array.get(i).pref){
    		array.get(i).city=k;
    		k++;
    	}else{
    		tmp = array.get(i).pref;
    		array.get(i).city=1;
    		k=2;
    	}
    }
    
    for(int i=0; i<m;i++){
    	System.out.println(String.format("%06d",array.get(i).pref)+String.format("%06d",array.get(i).city));
    }
 
  }
  }