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 Java8 (OpenJDK 1.8.0) (judge verdict: Time Limit Exceeded)

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Scanner;
import java.util.Set;


public class Main{
	
	private static int N;
	private static int M;
    private static int[]P;
    private static int[]Y;
    private static List<Integer>tmpP;
    private static HashMap<Integer, ArrayList<Integer>> tmpY;
    private static String result;
	public static void main(String args[])
	{
		Scanner sc = new Scanner(System.in);
		N=sc.nextInt();
		M=sc.nextInt();
        P=new int[M];
        Y=new int[M];
        for(int i=0;i<M;i++)
        {
        	P[i]=sc.nextInt();
        	Y[i]=sc.nextInt();
        }
        tmpP=new ArrayList<Integer>();
        tmpY=new HashMap<Integer, ArrayList<Integer>>();      
        for(int i=0;i<M;i++)
        {
        	tmpP.add(P[i]);
        }
        Set set =new HashSet(tmpP);
        tmpP.clear();
        tmpP.addAll(set);
        for(int i=1;i<=N;i++)
        {
        	ArrayList<Integer>tmpY1=new ArrayList<Integer>();
        	for(int k=0;k<M;k++)
        	{
        		if(i==P[k])
        		{
        			tmpY1.add(Y[k]);	
        		}
        		if(k==M-1&&tmpY1.size()>0)
        		{
        			Collections.sort(tmpY1);
        			tmpY.put(i, tmpY1);
        		}
        	}
        }
        
      for(int i=0;i<M;i++){
        result=String.format("%6d", P[i]).replace(" ", "0"); 
        result+=String.format("%6d", compare(P[i],Y[i])+1).replace(" ", "0"); 
        System.out.println(result);
        } 
	}
	public static int compare(int k,int value)
	{
		int mid;
		int left=0;
		int len=0;
		int right=0;
		for(int i=0;i<tmpY.size();i++)
		{
			len=tmpY.get(k).size(); 
			right=len-1;
			while(left<=right)
			{
				 // 确保中点靠近区间的起点
		        mid = (right+left)/2;
		        // 如果找到则返回
		        for(int m=0;m<len;m++)
		        {
		        if(tmpY.get(k).get(mid) <value) left= mid+1;
		        // 将中点赋给终点
		        else if(tmpY.get(k).get(mid)  > value) right = mid-1;
		        // 将中点加一赋给起点
		        else return mid;
		        }
			}
	    }
		return 0;
	}
}