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)

class City
  attr_accessor :prefec, :year, :spot, :rank
  def initialize prefec,year,spot
    self.prefec = prefec
    self.year = year

    # 自分が何番目に表示されるべきか
    self.spot = spot
  end
  def getID
    return "%06d%06d" % [self.prefec,self.rank]
  end
end

datas = gets.split(" ").map{|nn|nn.to_i}
n = datas[0]
m = datas[1]
cities = []

m.times do|spot|
  datas = gets.split(" ").map{|nn|nn.to_i}
  cities << City.new(datas[0],datas[1],spot)
end

prefecs = {}

cities.each do|cit|
  if prefecs[cit.prefec.to_s] != nil
    prefecs[cit.prefec.to_s] << cit
  else
    prefecs[cit.prefec.to_s] = [cit]
  end
end
prefecs.delete([])
prefecs.each do|cits|
  cits[1].sort!{|nn|nn.year}
  index = 1
  cits[1].each do|cit|
    cit.rank = index
    index += 1
  end
end
cities.sort!{|nn|nn.rank}
cities.each do|cit|
  puts cit.getID
end