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 PHP7 (7.0.15) (judge verdict: Wrong Answer)

<?php

fscanf(STDIN, "%d %d", $N, $M);

function addZero($input){
	return str_repeat("0", 6-strlen($input)).$input;
}

$array = array();
for ($i=0; $i < $M; $i++) { 
	$array[$i] = explode(" ", str_replace("\n", '', fgets(STDIN)));
}
$yearArray = array(array());
for ($j=1; $j <= $N; $j++) { 
	$count = 0;
	for ($k=0; $k < $M; $k++) { 
		if ($array[$k][0]==$j) {
			$yearArray[$j][$count]=[$array[$k][1],$k];
			$count++;
		}
	}
	sort($yearArray[$j], SORT_NUMERIC );
	for ($n=0; $n < $count; $n++) {
		$array[$yearArray[$j][$n][1]][2] = $n+1;
	}
}

for ($p=0; $p < $M; $p++) {
	echo addZero($array[$p][0]).addZero($array[$p][2])."\n";
}