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.Scanner;

public class Main
{
    public static void main(String[] args)
    {
        final Scanner sc = new Scanner(System.in);
        final int N = sc.nextInt();
        final int M = sc.nextInt();
        final long[][] original = new long[M][3];
        final long[] yearOrder = new long[M];
        for (int i = 0; i < M; i++)
        {
            original[i][0] = i;
            original[i][1] = sc.nextInt();
            original[i][2] = sc.nextInt();
            yearOrder[i] = original[i][2];
        }
        long order1;
        long order2;
        long order3;
        for (int i = 0; i < yearOrder.length; i++)
        {
            for (int j = 0; j <= i; j++)
            {
                if (yearOrder[j] > yearOrder[i])
                {
                    order1 = original[i][0];
                    order2 = original[i][1];
                    order3 = original[i][2];
                    yearOrder[i] = yearOrder[i] + yearOrder[j];
                    yearOrder[j] = yearOrder[i] - yearOrder[j];
                    yearOrder[i] = yearOrder[i] - yearOrder[j];

                    original[i][0] = original[j][0];
                    original[i][1] = original[j][1];
                    original[i][2] = original[j][2];

                    original[j][0] = order1;
                    original[j][1] = order2;
                    original[j][2] = order3;
                }
            }
        }

        final String[] answer = new String[M];
        String area;
        String yearOrderStr;
        long[] singleData;
        final long[] appearTimes = new long[N + 1];
        for (int i = 0; i < M; i++)
        {
            singleData = original[i];
            area = String.valueOf(singleData[1]);
            appearTimes[(int) singleData[1]]++;
            while (area.length() < 6)
            {
                area = "0" + area;
            }
            yearOrderStr = String.valueOf(appearTimes[(int) singleData[1]]);
            while (yearOrderStr.length() < 6)
            {
                yearOrderStr = "0" + yearOrderStr;
            }
            answer[(int) singleData[0]] = area + yearOrderStr;
        }
        for (final String singleResult : answer)
        {
            if (!"".equals(singleResult))
            {
                System.out.println(singleResult);
            }
        }
    }
}