Problem:
Score : 400 points

Problem Statement

Given is a tree G with N vertices.
The vertices are numbered 1 through N, and the i-th edge connects Vertex a_i and Vertex b_i.

Consider painting the edges in G with some number of colors.
We want to paint them so that, for each vertex, the colors of the edges incident to that vertex are all different.

Among the colorings satisfying the condition above, construct one that uses the minimum number of colors.

Constraints

2 \le N \le 10^5

1 \le a_i \lt b_i \le N

All values in input are integers.

The given graph is a tree.

Input

Input is given from Standard Input in the following format:

N
a_1 b_1
a_2 b_2
\vdots
a_{N-1} b_{N-1}

Output

Print N lines.

The first line should contain K, the number of colors used.

The (i+1)-th line (1 \le i \le N-1) should contain c_i, the integer representing the color of the i-th edge, where 1 \le c_i \le K must hold.

If there are multiple colorings with the minimum number of colors that satisfy the condition, printing any of them will be accepted.

Sample Input 1

3
1 2
2 3

Sample Output 1

2
1
2

Sample Input 2

8
1 2
2 3
2 4
2 5
4 7
5 6
6 8

Sample Output 2

4
1
2
3
4
1
1
2

Sample Input 3

6
1 2
1 3
1 4
1 5
1 6

Sample Output 3

5
1
2
3
4
5

Solution in Haskell (GHC 7.10.3) (judge verdict: Wrong Answer)

{-# LANGUAGE FlexibleContexts, ScopedTypeVariables #-}

import Control.Monad
import Control.Monad.State
import Data.List as L
import Data.Map as M
import Data.Maybe
import Data.Monoid
import Data.Set as S

infixl 9 !?
(!?) = flip M.lookup

main :: IO ()
main = do
  l1 <- getLine
  let n = read l1 :: Int
  ln <- sequence (replicate (n - 1) getLine)
  let abs = L.map (L.map read . words) ln :: [[Int]]
      (ans, (colors)) = runState (forM abs f) (M.empty)
      c = S.findMax $ S.unions $ M.elems colors

  print c
  forM_ ans print

f [a, b] = do
  (colors :: M.Map Int (S.Set Int)) <- get
  let uses = fromMaybe S.empty $ (colors !? a) `mappend` (colors !? b) :: S.Set Int
      c' = L.head $ L.dropWhile (`S.member` uses) [1..]

  put $ (M.insertWith S.union a (S.singleton c') $ M.insertWith S.union b (S.singleton c') colors)
  return c'