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;

namespace ABC113_C{
    class Program{
        static void Main(string[] args){
            int[] s = Array.ConvertAll(Console.ReadLine().Split(' '),int.Parse);
            int[][] arr = new int[s[1]][];
            int[] h = new int[s[0] + 1];

            for(var i = 0;i < s[1];i++){
                arr[i] = Array.ConvertAll((Console.ReadLine() + " " + i.ToString()).Split(' '),int.Parse);
            }

            Array.Sort(arr,(u,v) => u[1] - v[1]);
            for(var i = 0;i < s[1];i++){
                h[arr[i][0]]++;
                arr[i][1] = h[arr[i][0]];
            }
            Array.Sort(arr,(u,v) => u[2] - v[2]);

            for(var i = 0;i < s[1];i++){
                Console.WriteLine("{2}{0}{3}{1}",arr[i][0],arr[i][1],new string('0',6 - arr[i][0].ToString().Length),new string('0',6 - arr[i][1].ToString().Length));
            }
        }
    }
}