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: Time Limit Exceeded)

<?php
//error_reporting(0);
//$N = trim(fgets(STDIN));
list($N,$M) = explode(" ",trim(fgets(STDIN)));
//$H = explode(" ",trim(fgets(STDIN)));
for($i=0;$i<$M;$i++) {
  list($P[],$Y[]) = explode(" ",trim(fgets(STDIN)));
  $c = array('id'=>$i,'pref'=>$P[$i],'year'=>$Y[$i]);
  $city[]=$c;
}
usort($city,function($a,$b) {
  if ($a['pref']==$b['pref']) {
    return $a['year']-$b['year'];
  }
  return $a['pref']-$b['pref'];
});


foreach($P as $k=>$p) {
  printf("%06d%06d\n",$p,getPos($p,$k,$city));
}
function getPos($p,$k,$city) {
  $pos = 0;
  foreach($city as $c) {
    if ($p != $c['pref']) continue;
    if ($k == $c['id']) return $pos+1;
    $pos++;
  }
}