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.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;

class City {
	private int fP;
	private int fY;
	private int fFullId;
	private int fId;
	DecimalFormat dformat = new DecimalFormat("000000");

	public City(int p, int y, int fullId) {
		fP = p;
		fY = y;
		fFullId = fullId;
	}

	public int getY() {
		return fY;
	}

	public String getTextP() {
		return dformat.format(fP);
	}

	public int getP() {
		return fP;
	}

	public int getId() {
		return fId;
	}

	public String getTextId() {
		return dformat.format(fId);
	}

	public void setId(int id) {
		fId = id;
	}

	public int getfullId() {
		return fFullId;
	}
}

class compCity implements Comparator<City> {
	public int compare(City city1, City city2) {
		if (city1.getP() < city2.getP() || (city1.getP() == city2.getP() && city1.getY() < city2.getY())) {
			return -1;
		} else if (city1.getP() > city2.getP() || (city1.getP() == city2.getP() && city1.getY() > city2.getY())) {
			return 1;
		} else {
			return 0;
		}
	}
}

class compId implements Comparator<City> {
	public int compare(City city1, City city2) {
		if (city1.getfullId() < city2.getfullId()) {
			return -1;
		} else if (city1.getfullId() > city2.getfullId()) {
			return 1;
		} else {
			return 0;
		}
	}
}

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		int M = sc.nextInt();
		ArrayList<City> cityList = new ArrayList<City>(N);
		for (int i = 0; i < M; i++) {
			int p = sc.nextInt();
			int y = sc.nextInt();
			cityList.add(new City(p, y, i));
		}
		sc.close();

		Collections.sort(cityList, new compCity());

		int id = 1;
		int nowP = cityList.get(0).getP();
		for (int i = 0; i < M; i++) {
			if (nowP == cityList.get(i).getP()) {
				cityList.get(i).setId(id);
				id++;
			} else {
				nowP = cityList.get(i).getP();
				id = 1;
				cityList.get(i).setId(id);
				id++;
			}
		}

		Collections.sort(cityList, new compId());

		for (int i = 0; i < M; i++) {
			System.out.println(cityList.get(i).getTextP() + cityList.get(i).getTextId());
		}

	}
}