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.LinkedHashMap;
import java.util.LinkedList;
import java.util.Map;
import java.util.Scanner;
import java.util.TreeMap;
import java.util.Map.Entry;

public class Main {
	static int N, M;

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();
		M = sc.nextInt();
		Map<Integer, Integer> ml = new LinkedHashMap<Integer, Integer>();
		Map<Integer, String> result = new LinkedHashMap<Integer, String>();
		Map<Integer, Integer> m = new TreeMap<Integer, Integer>();
		for (int i = 0; i < M; i++) {
			int pi = sc.nextInt();
			int yi = sc.nextInt();
			ml.put(yi, pi);
			m.put(yi, pi);
		}
		int count;
		String xiaquid, cityorder, cityid;
		
//		for (Entry<Integer, Integer> entry : m.entrySet()) {
//			
//			System.out.print(entry.getKey()+"------");
//			System.out.println(entry.getValue());
//					}

		for (int i = 1; i <= N; i++) {
			count = 0;
			LinkedList<Integer> linkedList = new LinkedList<Integer>();
			for (Entry<Integer, Integer> entry : m.entrySet()) {
				int v = entry.getValue();
				Integer k = entry.getKey();
				if (i == v) {
					count++;
					xiaquid = String.format("%06d", Integer.valueOf(v));
					cityorder = String.format("%06d", Integer.valueOf(count));
					cityid = xiaquid + cityorder;
					result.put(k, cityid);
					linkedList.add(k);
				}

			}
			
			for(Integer item : linkedList){
	        	m.remove(item);
	        }

		}
		for (Entry<Integer, Integer> entry : ml.entrySet()) {
			System.out.println(result.get(entry.getKey()));
		}

	}

}