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: Time Limit Exceeded)

<?php
class In {
    private $array = [];
    private $length = 0;
    private $count = 0;

    function __construct()	{
        while (!feof(STDIN)) {
            $str = trim(fgets(STDIN));
            $this->array = array_merge($this->array, explode(' ', $str));
        }
        $this->length = count($this->array);
    }
    
    public function get(int $i){
        $this->array[$i];
    }

    public function next() {
        return $this->array[$this->count++];
    }
    public function hasNext() {
        return $this->count < $this->length;
    }
    public function nextInt() {
        return (int)$this->next();
    }
    public function nextDouble() {
        return (double)$this->next();
    }
    public function nextString() {
        return (string)$this->next();
    }
}

class Out {
    public static function line($str = "") {
        echo $str . PHP_EOL;
    }
}

$in = new In();

$total = $in->nextInt();
$length = $in->nextInt();
$array = [];
$array2 = [];

$i = 0;
while($in->hasNext()){
    $array[$in->nextInt()][] = [
        'num' => $in->nextInt(),
        "id" => $i++
    ];
}

$answer = [];
foreach ($array as $key => $value) {
    array_multisort(array_column($value, 'num'), SORT_ASC, $value);
    foreach ($value as $k => $v) {
        $answer[$v['id']] = sprintf('%06d', $key) . sprintf('%06d', $k + 1);
    }
}

for ($i = 0; $i < $length; ++$i) { 
    Out::line($answer[$i]);
}