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.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;

public class Main {

	static int ProvNum;
	static int CityNum;
	static int[] CityYear;
	static int[] CityOrder;
	static Map<Integer, List<Integer>> map;

	public static void main(String[] args) throws IOException {

		Scanner sc = new Scanner(System.in);

		ProvNum = sc.nextInt();
		CityNum = sc.nextInt();
		CityYear = new int[CityNum];
		CityOrder = new int[CityNum];
		map = new HashMap<Integer, List<Integer>>();
		for (int i = 0; i < CityNum; i++) {
			CityYear[i] = sc.nextInt();
			CityOrder[i] = sc.nextInt();
			if (map.containsKey(CityYear[i])) {
				map.get(CityYear[i]).add(CityOrder[i]);
			} else {
				List<Integer> list = new ArrayList<Integer>();
				list.add(CityOrder[i]);
				map.put(CityYear[i], list);
			}
		}
		for (Integer key : map.keySet()) {
			Collections.sort(map.get(key));
		}
		for (int j = 0; j < CityNum; j++) {
			List<Integer> orderList = map.get(CityYear[j]);
			int index = orderList.indexOf(CityOrder[j]) + 1;
			StringBuffer sb = new StringBuffer();
			String year = CityYear[j] + "";
			String number = index + "";
			if (year.length() < 6) {
				for (int k = 0; k < 6 - year.length(); k++) {
					sb.append("0");
				}
			}
			sb.append(year);
			if (number.length() < 6) {
				for (int k = 0; k < 6 - number.length(); k++) {
					sb.append("0");
				}
			}
			sb.append(number);
			System.out.println(sb.toString());
		}
	}
}