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.*;
import java.util.Arrays;
import java.util.ArrayList;
import java.util.Collections;
public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int m = sc.nextInt();
        int[] p = new int[m];
        long[] y = new long[m];
        long[] z = new long[m];
        for(int i = 0; i < m; i++){
            p[i] = sc.nextInt();
            y[i] = sc.nextLong();
            z[i] = y[i];
        }
        int[] ans1 = new int[m];
        int[] ans2 = new int[m];
        for(int i = 0; i < m; i++){
            ans1[i] = p[i];
        }
        Arrays.sort(z);
        for(int i = 0; i < m; i++){
            for(int j = 0; j < m; j++){
                if(y[i] == z[j]){
                    ans2[i] = j;
                }
            }
        }
        for(int i = 0; i < m; i++){
            for(int j = 0; j < m; j++){
                if(ans2[i] < ans2[j] && p[i] != p[j]){
                    ans2[j] --;
                }
            }
        }
        String[] Ans1 = new String[m];
        String[] Ans2 = new String[m];
        int[] len1 = new int[m];
        int[] len2 = new int[m];
        for(int i = 0; i < m; i++){
            Ans1[i] = String.valueOf(ans1[i]);
            Ans2[i] = String.valueOf(ans2[i]+1);
            len1[i] = Ans1[i].length();
            len2[i] = Ans2[i].length();
        }
        for(int i = 0; i < m; i++){
            while(len1[i] < 6){
                Ans1[i] = "0" + Ans1[i];
                len1[i] ++;
            }
            while(len2[i] < 6){
                Ans2[i] = "0" + Ans2[i];
                len2[i] ++;
            }
            System.out.println(Ans1[i] + Ans2[i]);
        }
    }
}