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.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
import java.util.Set;
import java.util.HashMap;
import java.util.TreeSet;
import java.util.ArrayList;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        ABC_113_C solver = new ABC_113_C();
        solver.solve(1, in, out);
        out.close();
    }

    static class ABC_113_C {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            int m = in.nextInt();

            List<Integer> years = new ArrayList<Integer>();

            String[] answerList = new String[m];
            Map<Integer, Integer> map = new HashMap<Integer, Integer>();
            Set<Integer> sortedYears = new TreeSet<Integer>();
            int[] townCity = new int[m];
            int[] city = new int[n];

            for (int i = 0; i < m; i++) {
                int p = in.nextInt();
                int year = in.nextInt();
                answerList[i] = String.format("%06d", p);
                townCity[i] = p;
                map.put(year, i);
//            years.add(year);
                sortedYears.add(year);
            }


            for (int year : sortedYears) {
                int pNumber = map.get(year);
//            int pNumber = years.indexOf(year);
                answerList[pNumber] += String.format("%06d", city[townCity[pNumber] - 1] + 1);
                city[townCity[pNumber] - 1]++;
            }

            for (String answer : answerList) {
                out.println(answer);
            }

        }

    }
}