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 qualified Data.Vector.Unboxed as U
import qualified Data.Vector as V
import qualified Data.ByteString.Char8 as C
import qualified Data.Array.IO as A
import Debug.Trace
import Data.List
import Data.Ord
import Control.Monad


r :: Int -> IO (U.Vector Int)
r n = U.unfoldrN n (C.readInt . C.dropWhile (==' ')) <$> C.getLine

r' :: IO [Int]
r'  =   unfoldr    (C.readInt . C.dropWhile (==' ')) <$> C.getLine


main :: IO ()
main = do
    [n,m] <- r'
    pys <- replicateM m $ do
        [p,y] <- r'
        return (p,y)
    let numPY = zip [1..] pys :: [(Int,(Int,Int))]
    let srtdPY = sortBy (comparing snd) numPY
    let rnkdPY = rank (fst (head srtdPY), 1) srtdPY
    let finPY = map snd $ sortOn fst rnkdPY
    mapM_ (putStrLn.showCity) finPY


rank :: (Int, Int) -> [(Int,(Int,Int))] -> [(Int,(Int,Int))]
rank _ [] = []
rank (cPref, ac) ((city,(pref,year)):xs)
    | pref==cPref = (city,(pref,ac)):(rank (pref,ac+1) xs)
    | otherwise   = (city,(pref,1 )):(rank (pref, 1+1) xs)

showCity :: (Int,Int) -> String
showCity (pref,rank) =
    let pS = show pref
        rS = show rank
        pI = 6 - (length pS)
        rI = 6 - (length rS)
    in  replicate pI '0' ++ pS ++ replicate rI '0' ++ rS