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.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Scanner;
public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int p;
		int n = sc.nextInt(), m = sc.nextInt();
		int[][] city = new int[n+1][100000];
		ArrayList<Integer> citylist = new ArrayList<Integer>();
		HashMap<Integer,Integer> cityrank = new HashMap<Integer,Integer>();
		HashMap<Integer,Integer> city_prefec = new HashMap<Integer,Integer>();
		int[] citycnt = new int[n+1]; //lengthでできる
		for(int i = 0;i < m;i ++) {
			int cnt = 0;
			p = sc.nextInt();
			city[p-1][citycnt[p-1]] = sc.nextInt();
			citylist.add(city[p-1][citycnt[p-1]]);
			cityrank.put(city[p-1][citycnt[p-1]], 1);
			city_prefec.put(city[p-1][citycnt[p-1]], p);
			for(int k = 0;k < citycnt[p-1];k++) {
				if(city[p-1][k] >= city[p-1][citycnt[p-1]]) {
					cityrank.put(city[p-1][k], cityrank.get(city[p-1][k])+1);
					cnt++;
				}else {
					cityrank.put(city[p-1][citycnt[p-1]], cityrank.get(city[p-1][k])+1);
				}
			}
			//if()
			citycnt[p-1]++;
		}
		for(int i = 0;i < m;i ++) { //県
			for(int k = 0;k < citycnt[i]; k++) {
				System.out.println(city[i][k]);
				//System.out.println();
			}
		}
		System.out.println(cityrank);
		/*for(int i = 0;i < m;i ++) { //県
			for(int k = 0;k < citycnt[i]; k++) {
				
				int plength = String.valueOf(i+1).length();
				int xlength = String.valueOf(tcnt).length();
				String s = "";
				for(int j = 0;j < 6-plength;j++) {
					s += "0";
				}
				s += String.valueOf(i+1);
				for(int j = 0;j < 6-xlength;j++) {
					s += "0";
				}
				s += String.valueOf(tcnt);
				System.out.println(s);
			}
		}*/
		for(int i = 0;i < m;i ++) {
			int prefecture = city_prefec.get(citylist.get(i));
			int citynum = cityrank.get(citylist.get(i));
			int plength = String.valueOf(prefecture).length();
			int xlength = String.valueOf(citynum).length();
			String s = "";
			for(int j = 0;j < 6-plength;j++) {
				s += "0";
			}
			s += String.valueOf(prefecture);
			for(int j = 0;j < 6-xlength;j++) {
				s += "0";
			}
			s += String.valueOf(citynum);
			System.out.println(s);
		}
		//System.out.println(city[i][k]);
		//System.out.println();
	}
}