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)

{-# OPTIONS_GHC -O2 -funbox-strict-fields #-}
import           Control.Monad.State.Strict
import qualified Data.ByteString.Char8      as B
import qualified Data.ByteString.Unsafe     as B
import           Data.Char                  (isSpace)
import qualified Data.Set                   as S
import qualified Data.Vector                as V
import qualified Data.Vector.Mutable        as VM
import qualified Data.Vector.Unboxed        as U

main :: IO ()
main = do
  [n, m] <- map read . words <$> getLine
  pys <- U.unfoldrN m parseInt2 <$> B.getContents
  putStr $ solve n m pys

solve :: Int -> Int -> U.Vector (Int, Int) -> String
solve n m pys = unlines . map (tail . show) $ U.toList ids
  where
    ids = U.map (\(p, y) -> encodeId p (S.findIndex y (ss V.! (p - 1)) + 1)) pys :: U.Vector Int
    ss = U.foldl' f (V.replicate n S.empty) pys :: V.Vector (S.Set Int)
    f ss' (p, y) = V.modify (\v -> VM.modify v (S.insert y) (p - 1)) ss'


encodeId :: Int -> Int -> Int
encodeId p r = 1000000000000 + p * 1000000 + r

type Parser a = B.ByteString -> Maybe (a, B.ByteString)

parseInt2 :: Parser (Int, Int)
parseInt2 = runStateT $
  (,) <$> StateT (B.readInt . B.dropWhile isSpace)
  <*> StateT (B.readInt . B.unsafeTail)