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)));
  $PY[$P[$i]][]=$Y[$i];
}
$sorted = array();
$PK = array();


foreach($P as $k=>$p) {
  printf("%06d%06d\n",$p,getPos($p,$k));
}
function getPos($p,$kkk) {
  global $sorted,$PY,$Y,$PK;
  if (!isset($sorted[$p])) {
    sort($PY[$p]);
    $sorted[$p]=1;
    foreach($Y as $k=>$y) {
      foreach($PY[$p] as $kk=>$v) {
        if ($y == $v) {
          $PK[$p][$y]=$kk;
        }
      }
    }
  }
  return $PK[$p][$Y[$kkk]]+1;
}