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: Accepted)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;

namespace ConsoleApp5
{
    class Program
    {
        int n;
        int inf = 1050000000;
        int result;
        int summ;
       
        int m,k,f;
        bool[,] pairs;
        int[,] g;
        List<int> tank;
        string a, b;
        char tmp;
        List<string> used;
        Dictionary<char, List<int>> tank1;
        int ans;

        public void Run()
        {
                var Elems = Console.ReadLine().Split().Select(int.Parse).ToArray();
                n = Elems[0];
                m = Elems[1];
            SortedDictionary<int, string>[] kek = new SortedDictionary<int, string>[n+1];
            SortedDictionary<int, string>[] lel = new SortedDictionary<int, string>[n + 1];
            for (int i = 1; i <= n; i++)
            {
                kek[i] = new SortedDictionary<int, string>();
                lel[i] = new SortedDictionary<int, string>();
            }
            List<string> list = new List<string>();
            for (int i = 0; i<m; i++)
            {
                list.Add(Console.ReadLine());
            }
            int[] pup;
            foreach (var e in list)
            {
                pup = e.Split().Select(int.Parse).ToArray();
                kek[pup[0]][pup[1]] = "";
                lel[pup[0]][pup[1]] = "";
            }
            int counter;
            for(int i = 1; i<=n; i++)
            {
                counter = 1;
                foreach (var e in kek[i])
                {
                    for (int j = 0; j < 6 - i.ToString().Length; j++)
                        lel[i][e.Key] += '0';
                    lel[i][e.Key] += i.ToString();
                    for (int j = 0; j < 6 - counter.ToString().Length; j++)
                        lel[i][e.Key] += '0';
                    lel[i][e.Key] += counter.ToString();
                    counter++;
                }
            }
                foreach (var e in list)
            {
                pup = e.Split().Select(int.Parse).ToArray();
                Console.WriteLine(lel[pup[0]][pup[1]]);
            }
        }

        
       
        void GoS(int i)
        {
        }

        /* string Kek(int i)
        {
            if (i == 1) return dp[1].ToString() + "+"+n;
            return "(" + Kek(i - 1) + ")" + dp[i].ToString() +"+"+ (n - i + 1).ToString();
        }
*/
        static void Main(string[] args)
        {
                    new Program().Run();
        }
    }
}