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 Haskell (GHC 7.10.3) (judge verdict: Time Limit Exceeded)

{-# LANGUAGE ScopedTypeVariables #-}
import Data.List
import Control.Monad

modif::Int->String
modif i = let n =  length (show i) in (take (6-n) (repeat '0'))++(show i)

sort_sort::[(Int,Int)]->[(Int,Int)]
sort_sort = (map (\ ((i,p),n) -> (p,n)) ).
            (sortBy (\ ((i1,_),_) -> \ ((i2,_),_) -> compare i1 i2)).
            concat.
            (map ((\ l -> zip l [1..]).map (\(i,(p,_))->(i,p)))).
            (map (sortBy (\ (_,(_,y1)) -> \ (_,(_,y2)) -> compare y1 y2))).
            (groupBy (\ (_,(p1,_)) -> \ (_,(p2,_)) -> p1 == p2)).
            (sortBy (\ (_,(p1,_)) -> \ (_,(p2,_)) -> compare p1 p2)).
            (zip [(1::Int) ..])

solver::[(Int,Int)]->[String]
solver = (map (\(p,n) -> (modif p)++(modif n))).sort_sort

main::IO()
main=do
  nmc<-getLine
  let n:m:[]=map read (words nmc)
  dat<-forM [1..m] (\_-> do
                    py<-getLine
                    let p:y:[]= map read (words py)
                    return (p,y))
  forM_ (solver dat) (\ str -> do
                                putStr str
                                putStr "\n")