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: Accepted)

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
	public static void main(String[] args){

		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int n = sc.nextInt();
		int m = sc.nextInt();

		List<City> citys = new ArrayList<>();
		int[] cityInPre = new int[n+1];
		for(int i=0;i<n+1;i++) {
			cityInPre[i]=0;
		}

		//double temp =0;
		//List<Double> list = new ArrayList<>();
		for(int i=0;i<m;i++) {
			City city = new City(i,sc.nextInt(),sc.nextInt());
			citys.add(city);
		}

		citys.sort((a,b) -> a.year-b.year);


		for(int i = 0;i<citys.size();i++) {
			citys.get(i).number = cityInPre[citys.get(i).prefecture]+1;
			cityInPre[citys.get(i).prefecture]++;
		}

		citys.sort((a,b) -> a.order-b.order);

		for(int i = 0;i<citys.size();i++) {
			String s = "";
			for(int j=0;j<5-Math.floor(Math.log10(citys.get(i).prefecture));j++) {
				s = s+"0";
			}
			s = s + Integer.toString(citys.get(i).prefecture);
			for(int j=0;j<5-Math.floor(Math.log10(citys.get(i).number));j++) {
				s = s+"0";
			}
			s = s + Integer.toString(citys.get(i).number);
			System.out.println(s);
		}


	}

}

class City{
	int order;
	int prefecture;
	int year;
	int number;
	City(int order,int prefecture, int year){
		this.order = order;
		this.prefecture = prefecture;
		this.year = year;
	}
}