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: Accepted)


import Data.Array (array, elems)
import Data.List (groupBy, sort)
import Control.Monad (forM_)

toSWithPad n x = replicate (n-l) '0' ++ s where
  s = show x
  l = length s

toC [x,y] = (x,y)
tw f x = f (f x)

gp :: [(Int,Int)] -> [[((Int,Int),Int)]]
gp = groupBy (\x y->fst (fst x)==fst (fst y)) . sort . flip zip [0..]

fi cs = go 1 cs where
  go n [] = []
  go n (((pref,year),i):cs) = (i,(pref,n)) : go (n+1) cs

solv n m cs = elems $ array (0,m-1) $ concat [fi cs'| cs' <- gp cs]

main = do
  [n,m] <- map read . words <$> getLine
  cs <- map (toC . map read . words) . lines <$> getContents :: IO [(Int,Int)]
  forM_ (solv n m cs) $ 
    \(pref,n) -> putStr (toSWithPad 6 pref) >> putStrLn (toSWithPad 6 n)