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: Time Limit Exceeded)

N,M=gets.chomp.split(" ").map(&:to_i)
p = []
y = []
arr = []
(1..M).each do |i|
  p[i], y[i] = gets.chomp.split(" ").map(&:to_i)
  if arr[p[i]].nil?
    arr[p[i]] = [{index: i, value: y[i]}]
  else
    arr[p[i]].push({index: i, value: y[i]})
  end
end
code_arr = []
arr[1..N].each.with_index(1) do |v, i|
  next if v.nil?
  res = v.sort_by{|vv| vv[:value]}
  res.each.with_index(1) do |vv, rank|
    ind = arr[i].find{|vvv| vvv[:value] == vv[:value] }[:index]
    code_arr[ind] = p[ind].to_s.rjust(6, '0') + rank.to_s.rjust(6, '0')
  end
end
code_arr.each do |c|
  print("#{c}\n")
end