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;

namespace AtCoder
{
    class Program
    {
        static void Main()
        {
            Solve();

            Console.ReadKey();
        }

        static void Solve()
        {
            var str = IO.GetIntList();
            var N = str[0];
            var M = str[1];

            long[][] pair = new long[M][];
            for(int i = 0; i < M; i++)
            {
                var hoge = IO.GetLongList();
                pair[i] = new long[4];
                pair[i][0] = hoge[0];
                pair[i][1] = hoge[1];
                pair[i][2] = i;
            }
            long[] P = Enumerable.Repeat((long)1, N).ToArray();
            pair = pair.OrderBy(p => p[1]).ToArray();
            for(int i = 0; i < M; i++)
            {
                pair[i][3] = P[pair[i][0]-1];
                P[pair[i][0]-1]++;
            }
            pair = pair.OrderBy(p => p[2]).ToArray();
            for(int i = 0; i < M; i++)
            {
                long num = 1000000000000 + pair[i][0] * 1000000 + pair[i][3];
                string ans = num.ToString();
                ans = ans.Substring(1, ans.Length - 1);
                Console.WriteLine(ans);
            }

            //Console.WriteLine(ans);
        }
    }


    static class IO
    {
        static public string GetString() { return Console.ReadLine(); }
        static public int GetInt() { return int.Parse(Console.ReadLine()); }
        static public long GetLong() { return long.Parse(Console.ReadLine()); }
        static public List<string> GetStringList() { return Console.ReadLine().Split(' ').ToList(); }
        static public List<int> GetIntList() { return Console.ReadLine().Split(' ').Select(int.Parse).ToList(); }
        static public List<long> GetLongList() { return Console.ReadLine().Split(' ').Select(long.Parse).ToList(); }
        static public List<double> GetDoubleList() { return Console.ReadLine().Split(' ').Select(double.Parse).ToList(); }
        static public void WriteStrings<T>(IEnumerable<T> values) { foreach (var o in values) { Console.Write(o + " "); } }
    }
}