Problem:
Score : 300 points

Problem Statement

Sitting in a station waiting room, Joisino is gazing at her train ticket.

The ticket is numbered with four digits A, B, C and D in this order, each between 0 and 9 (inclusive).

In the formula A op1 B op2 C op3 D = 7, replace each of the symbols op1, op2 and op3 with + or - so that the formula holds.

The given input guarantees that there is a solution. If there are multiple solutions, any of them will be accepted.

Constraints

0≤A,B,C,D≤9

All input values are integers.

It is guaranteed that there is a solution.

Input

Input is given from Standard Input in the following format:

ABCD

Output

Print the formula you made, including the part =7.

Use the signs + and -.

Do not print a space between a digit and a sign.

Sample Input 1

1222

Sample Output 1

1+2+2+2=7

This is the only valid solution.

Sample Input 2

0290

Sample Output 2

0-2+9+0=7

0 - 2 + 9 - 0 = 7 is also a valid solution.

Sample Input 3

3242

Sample Output 3

3+2+4-2=7

Solution in Haskell (GHC 7.10.3) (judge verdict: Accepted)

module Main where
import Control.Monad
import Control.Applicative
import Data.Maybe
import Data.List
import qualified Text.Printf
import qualified Data.ByteString.Char8 as BC
import qualified Data.ByteString as BC

------------------------------------------


main :: IO ()
main = do
  x:xs <- (map read <$> map (:[]) <$> getLine) :: IO [Int]
  let f a (x, s) = [(x+a, s ++ "+" ++ show a), (x-a, s ++ "-" ++ show a)]
      (_, ans) = head $ filter ((==) 7 . fst) $ foldl' (>>=) [(x, show x)] $ map f xs
  putStrLn $ ans ++ "=7"

------------------------------------------

{- Int input -}

parseInt :: BC.ByteString -> Int
parseInt = fst . fromJust . BC.readInt

parseInts :: BC.ByteString -> [Int]
parseInts = map parseInt <$> BC.words

readInt :: IO Int
readInt = parseInt <$> BC.getLine

readInts :: IO [Int]
readInts = parseInts <$> BC.getLine

{- Double Formatting -}

doubleFmt :: Double -> String
doubleFmt = Text.Printf.printf "%.12f"