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 Java (OpenJDK 11.0.6) (judge verdict: Wrong Answer)

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);

        // 県、市の数
        int kenAmount = scan.nextInt();
        int shiAmount = scan.nextInt();

        // 各市の県番号、誕生年、県内での誕生順を格納する2次元配列
        int shi[][] = new int[shiAmount][3];

        // 各市の認識番号(ID)を格納する配列
        long shiID[] = new long[shiAmount]; 

        // 各市の県番号、誕生年を標準入力から受け取り、誕生順と認識番号を0にセットする
        for(int i = 0; i < shi.length; i++) {
            shi[i][0] = scan.nextInt(); //県番号
            shi[i][1] = scan.nextInt(); //誕生年 
            shi[i][2] = 0; //誕生順
            shiID[i]  = 0; //ID
        }

        // 各市の県内での誕生順を調べる
        for(int i = 0; i < shi.length; i++) {
            // 値を1にセット
            shi[i][2] = 1;
            
            // i-1番目以前の要素と比較
            for(int j = 0; j < i; j++) {
                // iとjの県番号が同じとき
                if(shi[i][0] == shi[j][0]) {
                    // 誕生順がi, jならjの誕生順をインクリメントする
                    // そうでなければiの誕生順をインクリメントする
                    if(shi[i][1] < shi[j][1]) {
                        shi[j][2]++;
                    } else {
                        shi[i][2]++;
                    }
                }
            }
        }
        
        // 各市のIDを県番号と誕生順をもとに求めてshiIDに格納し、12桁で出力する
        for(int i = 0; i < shi.length; i++) {
            shiID[i] = 1000000 * shi[i][0] + shi[i][2];
            System.out.println(String.format("%012d", shiID[i]));
        }

        scan.close();
        return;
    }
}