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
list($n, $m) = explode(" ", trim(fgets(STDIN)));
for($i = 0; $i < $m; $i++){
    list($p, $y) = explode(" ", trim(fgets(STDIN)));
    $data[] = [$p, $y];
    $map[$p][$i] = $y;
}
foreach($map as &$m){
    sort($m);
}
foreach($data as $row){
    printf("%06d%06d\n", $row[0], 1+bsearch($row[1], $map[$row[0]]));
}
//o(bsearch(3,[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]));

function bsearch($key, &$haystack){
    $min = 0;
    $max = count($haystack);
    while(true){
        $c = round(($min + $max) / 2);
//        o($c);
        if($haystack[$c] == $key){
            return $c;
        }elseif($haystack[$min] > $key){
            $min = $c+1;
        }else{
            $max = $c-1;
        }
    }
}