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.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		@SuppressWarnings("unused")
		int N = Integer.parseInt(sc.next());
		int M = Integer.parseInt(sc.next());
		List<int[]> list1 = new ArrayList<>();

		StringBuilder buf = new StringBuilder();
		String s1 = "0";
		String s = "";

		for(int i=0; i<M;i++) {
			int a[] = new int[3];
			a[0] = Integer.parseInt(sc.next());
			a[1] = Integer.parseInt(sc.next());
			a[2] = i;
			list1.add(a);
		}
		List<int[]> list2 = new ArrayList<>(list1);
		List<int[]> list3 = new ArrayList<>();

		list2.sort((a1,a2)->a1[0]-a2[0]);
		int cnt=0,before0=0;
		for(int[]a:list2) {
			int b[] = new int[3];

			if(before0 < a[0]) {
				cnt=1;
			}else {
				cnt++;
			}

			before0 = a[0];
			b[0] = a[0];
			b[1] = cnt;
			b[2] = a[2];
			list3.add(b);

		}

		cnt=0;
		list3.sort((a1,a2)->a1[2]-a2[2]);
		for(int[]a:list3) {
			int keta = String.valueOf(a[0]).length();
			for(int i = 6;i>keta;i--) {
				buf.append(s1);
			}
			buf.append(a[0]);
			keta = String.valueOf(a[1]).length();
			for(int i = 6;i>keta;i--) {
				buf.append(s1);
			}
			buf.append(a[1]+"\n");

			s += buf.toString();
			if(cnt == 20) {

				System.out.println(s);
				s = "";
				cnt = 0;
			}else {
				cnt++;
			}
			buf.setLength(0);
		}
		System.out.println(s);

		sc.close();
	}

}