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 Ruby (2.3.3) (judge verdict: Wrong Answer)

# https://abc113.contest.atcoder.jp/tasks/abc113_c

temp = gets.chomp.split(" ").map{|x| x.to_i}
prefecture_count = temp[0]
city_count = temp[1]
prefecture_city_array_database = Array.new().map{Array.new()}

#p prefecture_city_array_database

# 問題文の順番を保存
city_count.times do |i|
   prefecture_city_array_database[i] = gets.chomp.split(" ").map{|x| x.to_i}
   prefecture_city_array_database[i].push(i)
end

#p prefecture_city_array_database

prefecture_city_array_database.sort_by! {|x| [x[0],x[1]]}

#p prefecture_city_array_database

prefecture_number = 1
push_number = 1
# ソート時の順番を保存
city_count.times do |i|
    if prefecture_number != prefecture_city_array_database[i][0]
        push_number = 1
        prefecture_number += 1
    end
    prefecture_city_array_database[i].push(push_number)
    push_number += 1
end


prefecture_city_array_database.sort_by! {|x| x[2]}

#p prefecture_city_array_database

city_count.times do |i|
    puts prefecture_city_array_database[i][0].to_s.rjust(6,"0") + prefecture_city_array_database[i][3].to_s.rjust(6,"0")
end