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)

def tst(n,m,ls)
  ys={}
  lines=[]
  for i in 0..ls.length-1
    p,y=ls[i].chomp.split(" ").map(&:to_i)
    lines<<{i: i, y: y, p: p.to_s}
    ys[p] ||= []
    ys[p] << y
  end
  ys.each_pair{|_,v|v.sort!}
  lines.each do |x|
    yv=ys[x[:p].to_i].index {|yy| x[:y]==yy }.next.to_s
    puts "#{x[:p].rjust(6-x[:p].length, "0")}#{yv.rjust(6-yv.length, "0")}"
  end
end

n,m=gets.chomp.split(" ").map(&:to_i)
ls=[]
while l=gets
  ls<<l unless l.chomp == ""
end
tst(n,m,ls)