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.*;
import java.io.*;

public class Main {

  public static void main (String[] args) {

    Scanner sc = new Scanner(System.in);

    int N = Integer.parseInt(sc.next());
    int M = Integer.parseInt(sc.next());
    int[] P = new int[M];
    int[] Y = new int[M];

    TreeMap<Integer, Integer> map = new TreeMap<>();

    for (int i = 0; i < M; i++) {
      P[i] = Integer.parseInt(sc.next());
      Y[i] = Integer.parseInt(sc.next());
      map.put(Y[i],P[i]);
    }

    sc.close();

    PrintWriter out = new PrintWriter(System.out);

    for (int i = 0; i < M; i++) {
      int j = 1;
      for (Map.Entry<Integer, Integer> m_ : map.entrySet()) {
        if(m_.getKey() == Y[i]){
          break;
        } else {
          if (m_.getValue() == P[i]){
            j++;
          }
        }
      }
      out.println(String.format("%06d", P[i]) + String.format("%06d", j));
    }

    out.flush();

  }

}