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.Map;
import java.util.Scanner;
import java.util.TreeMap;

public class Main {
	public static void main(String[]args) {
		try(Scanner scan = new Scanner(System.in)){
			int N = scan.nextInt();
			int M = scan.nextInt();
			
			int[]P = new int[M];
			int[]Y = new int[M];
			int[]p = new int[M];
			int[]y = new int[M];
			
			Map<Integer,Map<Long,Integer>>D = new TreeMap<Integer,Map<Long,Integer>>();
			for(int i = 1;i<=M;i++) {
				D.put(i, new TreeMap<Long,Integer>());
			}
			for(int i = 0;i<M;i++) {
				P[i] = scan.nextInt();
				Y[i] = scan.nextInt();
				D.get(P[i]).put((long)Y[i], i+1);
			}
			/*
			for(Integer key:D.keySet()) {
				int count = 1;
				for(Long a:D.get(key).keySet()) {
					int s = D.get(key).get(a);
					p[s-1] = key;
					y[s-1] = count;
					count++;
				}
			}
			*/
			for(int i = 0;i<M;i++) {
				String pi = String.valueOf(p[i]);
				String yi = String.valueOf(y[i]);
				StringBuffer sb = new StringBuffer();
				for(int j =0;j<6-pi.length();j++)sb.append('0');
				sb.append(pi);
				for(int j =0;j<6-yi.length();j++)sb.append('0');
				sb.append(yi);
				
				System.out.println(sb.toString());
				
			}
			
			
			
			
			
			
		}
		
		
	}
		

}