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.Scanner;
public class Main {
  public static void main( String[] args ) {
	  Scanner scan = new Scanner(System.in);
	  int N = scan.nextInt();
	  int M = scan.nextInt();
	  int[] P = new int[M];
	  int[] Y = new int[M];
	  int[] P_copy = new int[M];
	  int[] Y_copy = new int[M];
	  for( int i = 0; i < M; i++ ) {
		  P[i] = scan.nextInt();
		  Y[i] = scan.nextInt();
	  }
	  for( int i = 0; i < M; i++ ) {
		  P_copy[i] = P[i];
		  Y_copy[i] = Y[i];
	  }
	  for( int i = 0; i < M - 1; i++ ) {
		  for( int j = i + 1; j < M; j++ ) {
			  int p_tmp;
			  int y_tmp;
			  if( P_copy[i] > P_copy[j] ) {
				  p_tmp = P_copy[i];
				  P_copy[i] = P_copy[j];
				  P_copy[j] = p_tmp;
				  y_tmp = Y_copy[i];
				  Y_copy[i] = Y_copy[j];
				  Y_copy[j] = y_tmp;
			  }
		  }
	  }

	  for( int i = 0; i < M - 1; i++ ) {
		  for( int j = i + 1; j < M; j++ ) {
			  int p_tmp;
			  int y_tmp;
			  if( Y_copy[i] > Y_copy[j] && P_copy[i] == P_copy[j] ) {
				  p_tmp = P_copy[i];
				  P_copy[i] = P_copy[j];
				  P_copy[j] = p_tmp;
				  y_tmp = Y_copy[i];
				  Y_copy[i] = Y_copy[j];
				  Y_copy[j] = y_tmp;
			  }
		  }
	  }
	  String[] ans = new String[M];
	  for( int i = 0; i < ans.length; i++ )ans[i] = "";
	  int x = 1;
	  int tmp = 0;
	  for( int i = 0; i < M; i++ ) {
		  if( tmp != P_copy[i] ) {
			  tmp = P_copy[i];
			  x = 1;
		  }
		  for( int j = 0; j < M; j++ ) {
			  if( P_copy[i] == P[j] && Y_copy[i] == Y[j] ) {
				  ans[j] = String.format("%06d%06d", P_copy[i], x );
				  x++;
				  break;
			  }
		  }
	  }
	  for( int i = 0; i < M; i++ ) {
		  System.out.println( ans[i] );
	  }
  }
}