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: Accepted)

N, M = gets.split.map(&:to_i)
p = []
y = []
# 県=>市の配列 のハッシュ
c = {}
# ソートしちゃうので何番目に入力された市か覚えておく必要がある
# yearはユニークなので，year=>入力順の辞書を作っておく
dict = {}

M.times do |i|
  p[i], y[i] = gets.split.map(&:to_i)
  if c[p[i]].nil?
    c[p[i]] = []
  end
  c[p[i]].push(y[i])
  dict[y[i]] = i
end

c.each do |a|
  # 各県の市を誕生順に昇順ソートする
  a[1].sort!
end

# puts "#{c}"

ans = {}
c.each do |key, val|
  i = 1
  val.each do |v|
    ans[dict[v]] = format('%06d', key) + format('%06d', i)
    i += 1
  end
end

ans = ans.sort

ans.each do |a|
  puts a[1]
end