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: Runtime Error)

import java.util.Arrays;
import java.util.HashMap;
import java.util.Scanner;

class Main{
	public static void main(String[] args) {
		Scanner sc=new Scanner(System.in);
		int N=sc.nextInt();
		int M=sc.nextInt();
		long[] moto=new long[M];
		long[] sort=new long[M];
		int[] kosu=new int[100001];
		HashMap<Long,Long> unko=new HashMap<Long,Long>(M*4/3+1);

		for(int i=0; i<=100000; i++) {
			kosu[i]=0;
		}
		for(int i=0; i<M; i++) {
			long a=sc.nextLong();
			long b=sc.nextLong();
			kosu[(int)a]++;
			moto[i]=a*1000000+b;
			sort[i]=moto[i];
		}
		Arrays.sort(sort);
		for(int i=0; i<M; i++) {
			unko.put(sort[i], (long)(i+1));
		}

		for(int i=0; i<M; i++) {
			long ans=unko.get(moto[i]);
			long tmp=moto[i]/1000000;
			ans-=kosu[(int) tmp-1];
			String ans1=String.format("%06d", tmp);
			String ans2=String.format("%06d", ans);
			System.out.println(ans1+ans2);
		}
	}
}