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: Accepted)

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map.Entry;
import java.util.Scanner;
import java.util.SortedMap;
import java.util.TreeMap;

public class Main {

	public static class Point {
		public Point(int p, int y) {
			this.p = p;
			this.y = y;
		}

		int p, y;
	}

	private static int N;
	private static int M;
	private static HashMap<Integer, SortedMap<Integer, Integer>> tmpMap = new HashMap<>();

	public static void main(String args[]) {
		Scanner sc = new Scanner(System.in);
		N = sc.nextInt();
		M = sc.nextInt();

		List<Point> list = new ArrayList<>();
		for (int i = 0; i < M; i++) {
			int p = sc.nextInt();
			int y = sc.nextInt();
			list.add(new Point(p, y));
			SortedMap<Integer, Integer> treemap;
			if (tmpMap.containsKey(p)) {
				treemap = tmpMap.get(p);
			} else {
				treemap = new TreeMap<>();
			}
			treemap.put(y, 0);
			tmpMap.put(p, treemap);
		}

		for (Entry<Integer, SortedMap<Integer, Integer>> item : tmpMap.entrySet()) {
			int i = 0;
			Iterator<Entry<Integer, Integer>> iterator = item.getValue().entrySet().iterator();
			while (iterator.hasNext()) {
				iterator.next().setValue(++i);
			}
		}
		for (Point point : list) {
			int p = point.p;
			String string1 = "000000" + p;
			String string2 = "000000" + tmpMap.get(p).get(point.y);
			System.out.println(string1.substring(string1.length() - 6) + string2.substring(string2.length() - 6));
		}
	}
}