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: Accepted)

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

class Main{
	static int n;
	static long ans = 1000000000;
	static int[] memo;
	static int[] dp;
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);			//文字の入力
		int N = sc.nextInt();
		int M = sc.nextInt();
		int[] P = new int[M];
		int[] Y = new int[M];
		int[] count = new int[N];				//県ごとの市の生まれた順番を記憶
		Map<Integer, Integer> map = new TreeMap<>();
		for(int i = 0;i < M;i++){
			P[i] = sc.nextInt();
			Y[i] = sc.nextInt();
			map.put(Y[i], i);
		}
		int num;
		int index = 0;
		for(Integer value :map.values()){
			index = value;			//初期の順番
			num = P[index]-1;
			if(count[num] == 0){				//もしその県にまだ何も生まれてなかったら
				count[num] = 1;
				Y[index] = count[num];			//順番(1番目)を記憶
			}else{
				count[num]++;
				Y[index] = count[num];			//順番を記憶
			}
		}
		
		for(int i = 0;i < M;i++){
			System.out.println(String.format("%06d%06d", P[i],Y[i]));
		}


	}
}







class Pair implements Comparable{
	int from;		//p
	int end;		//y
	int num;
	int bango;
	@Override
	public int compareTo(Object other) {
		Pair otherpair = (Pair)other;

		return end - otherpair.end;
	}
}