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 PHP (5.6.30) (judge verdict: Wrong Answer)

<?php
// スペース区切りの整数の入力
fscanf(STDIN, "%d %d", $n, $m);

$data = array();
for ($i = 0; $i < $m; $i++) {
  $data[] = fscanf(STDIN, "%d %d");
}

for ($i = 1; $i <= $n; $i++) {
  $pref_data = array();
  foreach ($data as $j => $a) {
    if ($a[0] === $i) {
      $pref_data[] = array(
        'index' => $j,
        'year' => $a[1],
      );
    }
  }
  var_dump($pref_data);
  if (!empty($pref_data)) {
    //多次元配列のソート
    foreach ($pref_data as $key => $value) {
      $sort[$key] = $value['year']; //yearでソート
    }

    array_multisort($sort, SORT_ASC, $pref_data);

    $k = 1;
    $id_first = sprintf('%06d', $i);
    foreach ($pref_data as $pref) {
      $id_last = sprintf('%06d', $k);
      $data[$pref['index']][2] = $id_first. $id_last;
      $k++;
    }
  }
}

foreach ($data as $a) {
  echo $a[2]."\n";
}

?>