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: Runtime Error)

# n 県数
# m 市数
n, m = gets.split.map(&:to_i)

ken = {}
data = m.times.map.with_index do |i|
  p, y = gets.split.map(&:to_i)
  ken[p] ||= []
  ken[p] << [i, y]
  [p, y]
end

# pp data
pp ken

ken.each do |p, value|
  value
    .sort_by {|(data_index, year)|  year } # sort with year
    .each.with_index(1) do |(data_index, year), order|
      # pp [data_index, year, order]

      # pp [p, data_index, order]
      # pp ({ ken: p, data_index: data_index, order: order, year: data[data_index][1] })

      data[data_index][2] = order
    end
end

data.each do |(p, _y, o)|
  puts "%06d%06d" % [p, o]
end