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.awt.*;
import java.util.*;

public class Main {

    public static void main(String[] args) {
        // write your code here
        Scanner sc = new Scanner(System.in);

        // abc 113 C 連想配列っぽくやる?

        int n = sc.nextInt();
        int m = sc.nextInt();
        Point[] junban = new Point[m];

        Map<Integer, ArrayList<Integer>> list = new HashMap<>();

        for (int i = 0; i < m; i++) {
            int p = sc.nextInt();
            int year = sc.nextInt();
            junban[i] = new Point(p, year);
            ArrayList<Integer> value = list.get(p);
            if (value == null) {
                value = new ArrayList<>();
            }
            value.add(year);
            list.put(p, value);
        }

        for(Integer key : list.keySet()) {
            ArrayList<Integer> l = list.get(key);
            Collections.sort(l);
        }

        for (int i = 0; i < m; i++) {
            Point p = junban[i];
            StringBuilder builder = new StringBuilder();
            for (int j = 0; j < 6 - String.valueOf(p.x).length(); j++) {
                builder.append(0);
            }
            builder.append(p.x);
            int v = list.get(p.x).indexOf(p.y) + 1;
            for (int j = 0; j <  6 - String.valueOf(v).length(); j++) {
                builder.append(0);
            }
            builder.append(v);
            System.out.println(builder);
        }
    }
}