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.*;

class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = Integer.parseInt(sc.next());
		int M = Integer.parseInt(sc.next());
		Comparator<int[]> comparator_0 = new Comparator<int[]>() {
		    @Override
		    public int compare(int[] o1, int[] o2) {
		        return Integer.compare(o1[0], o2[0]);
		    }
		};
		Comparator<int[]> comparator_1 = new Comparator<int[]>() {
		    @Override
		    public int compare(int[] o1, int[] o2) {
		        return Integer.compare(o1[1], o2[1]);
		    }
		};
		Comparator<int[]> comparator_2 = new Comparator<int[]>() {
		    @Override
		    public int compare(int[] o1, int[] o2) {
		        return Integer.compare(o1[2], o2[2]);
		    }
		};
		ArrayList<int[]> list = new ArrayList<int[]>();
		for (int i=0;i<M;i++) {
			int P = Integer.parseInt(sc.next());
			int Y = Integer.parseInt(sc.next());
			int[] tmp = {i, P, Y , 0};
			list.add(tmp);
		}
//		Collections.sort(list, comparator_2);
//		Collections.sort(list, comparator_1);
		int index=1;
		int former=0;
		// for (int i=0;i<M;i++) {
		// 	int value_1=list.get(i)[1];
		// 	int value_3=list.get(i)[3];
		// 	if (former==value_1) {
		// 		index++;
		// 		value_3=index;
		// 		former=value_1;
		// 	} else {
		// 		index=1;
		// 		value_3=index;
		// 		former=value_1;
		// 	}
		// }

//		Collections.sort(list, comparator_0);
		for (int i=0;i<M;i++) {
			System.out.printf("%06d%06d",list.get(i)[1],list.get(i)[3]);
			System.out.println("");
		}
	}
}