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 C# (Mono 4.6.2.0) (judge verdict: Time Limit Exceeded)

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using static System.Console;
using static System.Math;

// 

public class Program_ABC113_C // ←Class名変更！！
{
    public static void Main()
    {
        var xy = ReadLine().Split(' ');
        var n = int.Parse(xy[0]);  //x,y なのか y,xなのか注意
        var m = int.Parse(xy[1]);

        //var s = new SortedList();
        //s.IndexOfValue

        var pyd = new Dictionary<int, List<int>>();
        var ipy = new Dictionary<int, int[]>();
        for (int i = 0; i < m; i++)
        {
            var py = ReadLine().Split(' ');
            var p = int.Parse(py[0]);  //x,y なのか y,xなのか注意
            var y = int.Parse(py[1]);

            ipy.Add(i, new[] { p, y });

            if (!pyd.ContainsKey(p))
            {
                pyd[p] = new List<int>();
            }

            pyd[p].Add(y);

        }

        foreach (var item in pyd)
        {
            item.Value.Sort();
        }

        foreach (var item in ipy)
        {
            var p = item.Value[0];
            var y = item.Value[1];
            var rank = pyd[p].IndexOf(y) + 1;
            WriteLine($"{p.ToString("000000")}{rank.ToString("000000")}");


        }



    } // Main

}     // Class