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.util.ArrayList;
import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int N = sc.nextInt();
		int M=sc.nextInt();
		ArrayList<City> Cities=new ArrayList<City>();
		// スペース区切りの整数の入力
		for(int i=0;i<M;i++) {
			int b = sc.nextInt();
			int c = sc.nextInt();
			int k=1;
			for(City city:Cities) {
				if(b==city.ken) {
					if(c<city.year) {
						city.renew(city.num+1);
					}else {
						k++;
					}
				}

			}
			Cities.add(new City(b,c,k));

		}
		// 文字列の入力
		//String s = sc.next();
		for(City city:Cities) {
			System.out.printf("%06d%06d\n", city.ken,city.num);
		}
	}
}
class City{
	int num;
	int year;
	int ken;
	City(int K,int Y,int N){
		ken=K;
		year=Y;
		num=N;
	}
	void renew(int N) {
		num=N;
	}
}
/*class CityCompare implements Comparator<City>{
	@Override
	public int compare(City c1,City c2) {
		if(c1.year>c2.year) {
			return 1;
		}else {
			return -1;
		}
	}
}*/