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 (7.4.4) (judge verdict: Wrong Answer)

<?php
 fscanf(STDIN,"%d%d",$n,$m);
$citys = array();
 for($i=0;$i<$m;$i++){
   $p_y = explode(" ",trim(fgets(STDIN)));
   $pref[$p_y[0]][] = $p_y[1];
   $py_li[] = $p_y;
 }
 

//昇順にする
$p_y_key_li = array_keys($pref);
for($i=0;$i<count($p_y_key_li);$i++){
  asort($pref[$p_y_key_li[$i]]);
}


foreach($py_li as $py){
  $x = array_keys($pref[$py[0]], $py[1] , true);
  for($i=0;$i<6-strlen($py[0]);$i++){
    echo "0";
  }
  echo $py[0];
   for($i=0;$i<6-strlen($x);$i++){
    echo "0";
  }
  echo ($x[0]+1)."\n";
}
//print_r($pref);