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.Arrays;
import java.util.Scanner;

public class Main {

	static int N, M;
	static int[][] TABLE;
	static int[] PRECITY;

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();
		M = sc.nextInt();
		TABLE = new int[M][2];
		for (int i = 0; i < M; i++) {
			TABLE[i][0] = sc.nextInt();
			TABLE[i][1] = sc.nextInt();
		}
		PRECITY = new int[N];
		for (int i = 0; i < M; i++) {
			int preNo = TABLE[i][0];
			PRECITY[preNo - 1] += 1;
		}
		for (int i = 0; i < N; i++) {
			int[] tempArr = new int[PRECITY[i]];
			int arrTop = 0;
			for (int j = 0; j < M; j++) {
				if (TABLE[j][0] == i + 1)
					tempArr[arrTop++] = TABLE[j][1];
			}
			Arrays.sort(tempArr);
			for (int j = 0; j < M; j++) {
				int t1 = getIndex(TABLE[j][1], tempArr);
				if (t1 != -1)
					TABLE[j][1] = t1;
			}

		}
		for (int i = 0; i < TABLE.length; i++) {
			System.out.println(forMatSize("" + TABLE[i][0]) + forMatSize("" + TABLE[i][1]));
		}
	}

	public static String forMatSize(String str) {
		int len = ("" + str).length();
		for (int i = 0; i < 6 - len; i++) {
			str = "0" + str;
		}
		return str;
	}

	public static int getIndex(int num, int[] arr) {
		for (int i = 0; i < arr.length; i++) {
			if (num == arr[i])
				return i + 1;
		}
		return -1;
	}

}