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.Generic;
using System.Linq;

namespace abc113_c
{
	class Program
	{
		static void Main(string[] args)
		{
			int[] x = Console.ReadLine().Split().Select(int.Parse).ToArray();
			List<int>[] list = new List<int>[x[0]];
			for (int i = 0; i < x[0]; i++) list[i] = new List<int>();
			Tuple<int, int>[] city = new Tuple<int, int>[x[1]];
			for (int i = 0; i < x[1]; i++)
			{
				int[] a = Console.ReadLine().Split().Select(int.Parse).ToArray();
				list[a[0] - 1].Add(a[1]);
				city[i] = new Tuple<int, int>(a[0], a[1]);
			}
			for (int i = 0; i < x[0]; i++)
			{
				int[] arr = list[i].ToArray();
				Array.Sort(arr);
				list[i] = arr.ToList();
			}
			for (int i = 0; i < x[1]; i++)
			{
				Console.WriteLine(city[i].Item1.ToString("D6") + (list[city[i].Item1 - 1].IndexOf(city[i].Item2) + 1).ToString("D6"));
			}
		}
	}
}