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.Comparator;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int N = sc.nextInt();
		int M = sc.nextInt();

		int[] P = new int[N];
//		for(int i=0;i<N;i++) {
//			list.add(new ArrayList<>());
//		}



		List<City> li = new ArrayList<>();

		Main x = new Main();
		for(int i=0;i<M;i++) {
			li.add(x.new City(sc.nextInt(),sc.nextInt(),i));
		}


//		int[] nowKen = {0};
//		int[] nowNum = {0};


		Comparator<City> cityComparator =
	       Comparator.comparing(City::getPre)
              .thenComparing(Comparator.comparing(City::getYear));

//		System.out.println("リストこっから");

		li.stream()
	        .sorted(cityComparator)
	        .peek(c ->{
	        	c.setMyNum(++P[c.getPre()-1]);
	        })
	        .sorted((a,b) -> a.getOrderId()-b.getOrderId())

	        .forEach(i -> System.out.println(i));

// 		System.out.println(li);
		sc.close();
	}

	public class City{
		private int pre;
		private int year;
		private int orderId;
		private int myNum;

		public City(int pre, int year,int orderId) {
			super();
			this.pre = pre;
			this.year = year;
			this.orderId = orderId;
		}

		public int getPre() {
			return pre;
		}
		public int getYear() {
			return year;
		}
		public int getOrderId() {
			return orderId;
		}
		public int getMyNum() {
			return myNum;
		}
		public void setMyNum(int myNum) {
			this.myNum = myNum;
		}

		@Override
		public String toString() {
			// TODO 自動生成されたメソッド・スタブ
			return String.format("%06d%06d", this.getPre(),this.getMyNum());
//			return this.getPre() + this.getMyNum();
		}


	}
}