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)

def find_cr(arr, i)
    cnt = 0
    arr.each do |a|
        rank = 1
        a.each do |b|
            return [cnt,rank] if b[0] == i
            rank += 1
        end
        cnt += 1
    end
end

def cc
    n,m = gets.chomp.split(/\s/).map{|x| x.to_i}

    #py = {}
    #for i in 0..(n)
    #    py[i] = []
    #end

    py = []
    for i in 0..(n)
        py[i] = []
    end

    for i in 1..m
        pr, y = gets.chomp.split(/\s/).map{|x| x.to_i}
        py[pr].push([i-1, y])
        #py[pr].push([i-1, y])
    end

    for i in 0..(n)
        py[i] = py[i].sort {|a,b| (a[1] <=> b[1]).nonzero? || a[2] <=> b[2]}
    end
    #p py
    #p py.sort {|a,b| a[1].sort {|c,d| c[1]<=>d[1]} > b[1] }
    #p py.sort {|a,b| (a[1] <=> b[1]).nonzero? || a[2] <=> b[2]}

    for i in 0..(n)
        c,r = find_cr(py, i)
        print sprintf("%06d%05d\n",c, r)
    end
end

cc