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: Wrong Answer)

import java.util.Scanner;
import java.util.ArrayList;
import java.util.Arrays;
public class Main{
	public static void main(String[] args){
		Scanner scan = new Scanner(System.in);
		int n,m,i,j;
		n=scan.nextInt();
		m=scan.nextInt();
		long si[] = new long[m];
		long ans[]= new long[m];
		long ta=1000000;
		for(i=0;i<m;i++){
			long p,y;
			p=scan.nextInt();
			y=scan.nextInt();
			si[i]=p*ta*ta+y*ta+i;
		}
		Arrays.sort(si);
		long mae=0,ren=0;
		for(i=0;i<m;i++){
			if(si[i]/(ta*ta)!=mae){mae=si[i]/(ta*ta);ren=0;}
			ren++;
			ans[(int)(si[i]%ta)]=mae*ta+ren;
		}
		for(i=0;i<m;i++){
			String iti=Long.toString(ans[i]);
			for(j=iti.length();j<12;j++){System.out.print(0);}
			System.out.println(iti);
		}
	}
}