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 {
	
	public static void main(String args[])throws Exception{
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int M = sc.nextInt();
		int [][] City=new int[M][2];
		String string = "";

		int k=1;
		for(int i=0;i<M;i++) {
			City[i][0]=sc.nextInt();
			City[i][1]=sc.nextInt();
			string = string +City[i][0]+" ";
		}
			
		while(k<=N){
			if(string.contains(k+" ")){
				ArrayList<Integer> list = new ArrayList<>();
				for(int i=0;i<M;i++) {
					if(City[i][0]==k) {
						list.add(City[i][1]);
					}
				}
		        Collections.sort(list);
		        
				for(int i=0;i<M;i++) {
					if(City[i][0]==k) {
						for(int j=0;j<list.size();j++) {
							if(City[i][1]==list.get(j)){
								City[i][1]=j+1;
								break;
							}
						}
					}	
				}
			}
		    
			k=k+1;
		}
		
		for(int i=0; i<M;i++) {
			String str1=String.format("%06d", City[i][0]);
			String str2=String.format("%06d", City[i][1]);
			System.out.println(str1+str2);
		}

	}

}