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: Wrong Answer)

import Text.Printf
import Data.IORef
import Control.Monad
import Debug.Trace
import Data.Char

mytrace a = trace (show a) a

main :: IO ()
main = do
  [a, b, c, d] <- map digitToInt <$> getLine :: IO [Int]
  results <- newIORef []
  forM_ [1, 2] $ \i -> do
    let op1 = if i == 1 then (+) else (-)
    forM_ [1, 2] $ \j -> do
      let op2 = if j == 1 then (+) else (-)
      forM_ [1, 2] $ \k -> do
        let op3 = if k == 1 then (+) else (-)
        when ((op1 a $ op2 b $ op3 c d) == 7) $ do
          acc <- readIORef results
          writeIORef results ((i, j, k):acc)

  (i, j, k) <- head <$> readIORef results
  putStrLn $ printf "%d%s%d%s%d%s%d=7" a (opshow i) b (opshow j) c (opshow k) d

opshow :: Int -> String
opshow 1 = "+"
opshow 2 = "-"