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.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int N = scanner.nextInt();
		int M = scanner.nextInt();

		int[][] posArr = new int[M][2];
		for (int i = 0; i < M; i++) {
			posArr[i][0] = scanner.nextInt();
			posArr[i][1] = scanner.nextInt();
		}

		Map<Integer, ArrayList<Integer>> map = new HashMap<>();

		ArrayList<Integer> tmpList = new ArrayList<Integer>();
		for (int i = 0; i < M; i++) {
			if (map.containsKey(posArr[i][0])) {
				map.get(posArr[i][0]).add(posArr[i][1]);
			} else {
				tmpList = new ArrayList<Integer>();
				tmpList.add(posArr[i][1]);
				map.put(posArr[i][0], tmpList);
			}
		}

		for (Integer key : map.keySet()) {
			ArrayList<Integer> list = map.get(key);
			Collections.sort(list);
			map.put(key, list);
		}

		int key = 0;
		int val = 0;
		for (int i = 0; i < M; i++) {
			key = posArr[i][0];
			val = posArr[i][1];
			System.out.println(layout(key, map.get(key).indexOf(val)+1));
		}
	}
	
	private static String layout(int val1, int val2){
		StringBuffer stringBuffer = new StringBuffer("");
		int leftCount = 6 - Integer.toString(val1).length();
		for(int i=0; i<leftCount; i++){
			stringBuffer.append("0");
		}
		stringBuffer.append(val1);
		
		int rigthCount = 12 - Integer.toString(val2).length();
		for(int i=6; i<rigthCount; i++){
			stringBuffer.append("0");
		}
		stringBuffer.append(val2);
		return stringBuffer.toString();
	}
}