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 final long MOD = 1000000007;

	static int H, W, K;
	static long[][] dp = new long[110][10];
	static int ans = 0;
	static long n = 0;





	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();
		Map<Integer, Integer> map = new TreeMap<Integer,Integer>();
		int[] city = new int[n+1];			//県ごとの順番を記録
		int[] P = new int[m];
		int[] Y = new int[m]; 
		for(int i = 0;i < m;i++){
			int p = sc.nextInt();
			int y = sc.nextInt();
			P[i] = p;
			Y[i] = y;
			map.put(y, p);
		}
		for(Integer key : map.keySet()){
			int cc = map.get(key);				//県
//			System.out.println(cc);
//			System.out.println(map.get(key));

			map.put(key, city[cc]+1);
			city[cc]++;				//県での順番を+1
		}

		for(int i = 0;i < m;i++){
			System.out.println(String.format("%06d%06d",  P[i], map.get(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;
	}
}