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: Wrong Answer)


import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner();
		int n = sc.nextInt();
		int m = sc.nextInt();
		int[][] table = new int[m][2];
		Map<Integer, List<Integer>> map = new HashMap<>();

		for(int i=0; i < m; i++){
			int p = sc.nextInt();
			int y = sc.nextInt();
			table[i][0] = p;
			table[i][1] = y;
			List<Integer> l = new ArrayList<>();
			if(map.containsKey(p))
				l = map.get(p);
			l.add(y);
			map.put(p, l);
		}
		for(int i =0;i <= n; i++)
			if(map.containsKey(i))
				Collections.sort(map.get(i));


		for(int i=0; i < m; i++){
			String format = "%06d%06d";
			int p = table[i][0];
			int y = table[i][1];
			System.out.println(format(p) + format(map.get(p).indexOf(y)+1));
		}
	}
	private static String format(int num){
		String s = Integer.toString(num);
		for(int i =0;i + s.length() < 6; i++ )
			s = "0" + s;
		return s;
	}
}

class Scanner {
	private static final int SPACE = (int)' ';
	private static final int LINE_END_0 = 13;
	private static final int LINE_END_1 = 10;
	private static final int BEFORE = -1;
	private BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

	public String next(){
		StringBuilder sb = new StringBuilder();

		int length = BEFORE;
		readLoop: while(true) {
			try {
				int value = br.read();
				switch(value) {
				case LINE_END_1:
					if(length == BEFORE)
						break;

					if((int)sb.charAt(length) == LINE_END_0)
						sb.deleteCharAt(length);
				case SPACE:
					break readLoop;
				}
				sb.append((char)value);
				length++;

			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		return sb.toString();
	}

	public String[] nextArray(int length) {
		String[] array = new String[length];
		for(int i = 0; i < length; i++)
			array[i] = next();
		return array;
	}

	public double nextDouble() {
		return Double.parseDouble(next());
	}

	public double[] nextDoubleArray(int length) {
		double[] array = new double[length];
		for(int i = 0; i < length; i++)
			array[i] = nextDouble();
		return array;
	}

	public int nextInt() {
		return Integer.parseInt(next());
	}

	public int[] nextIntArray(int length) {
		int[] array = new int[length];
		for(int i = 0; i < length; i++)
			array[i] = nextInt();
		return array;
	}

	public long nextLong() {
		return Long.parseLong(next());
	}

	public long[] nextLongArray(int length) {
		long[] array = new long[length];
		for(int i = 0; i < length; i++)
			array[i] = nextLong();
		return array;
	}

	public boolean ready() {
		try {
			return br.ready();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return false;
	}
}