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.Scanner;

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

        int n = sc.nextInt();
        int m = sc.nextInt();
        int[][] py = new int[m][3];

        for (int i = 0; i < m; i++) {
            py[i][0] = sc.nextInt();
            py[i][1] = sc.nextInt();
            py[i][2] = i;
        }

        py = Ssort(py);
        String[] re = new String[m];

        int cnt = 1;
        for (int i = 0; i < m; i++) {
            int a = py[i][0];
            int b = py[i][2];
            if (i >= 1) {
                int a1 = py[i-1][0];
                if (a == a1)
                    cnt++;
                else
                    cnt = 1;
            }
            re[b] = String.format("%06d%06d", a, cnt);
        }

        for (String s : re) {
            System.out.println(s);
        }
    }

    public static int[][] Ssort(int[][] aOrigin) {
        int[][] a = aOrigin.clone();
        for (int i = 0; i < a.length-1; i++) {
            int max = i;
            for (int j = i; j < a.length; j++) {
                if (a[max][0] < a[j][0]) {
                    max = j;
                }
            }
            int num1 = a[max][0];
            int num2 = a[max][1];
            int num3 = a[max][2];
            a[max][0] = a[i][0];
            a[max][1] = a[i][1];
            a[max][2] = a[i][2];
            a[i][0] = num1;
            a[i][1] = num2;
            a[i][2] = num3;
        }

        for (int i = 0; i < a.length-1; i++) {
            int min = i;
            for (int j = i; j < a.length; j++) {
                if (a[min][1] > a[j][1]) {
                    min = j;
                }
            }
            int num1 = a[min][0];
            int num2 = a[min][1];
            int num3 = a[min][2];
            a[min][0] = a[i][0];
            a[min][1] = a[i][1];
            a[min][2] = a[i][2];
            a[i][0] = num1;
            a[i][1] = num2;
            a[i][2] = num3;
        }

        return a;
    }
}