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)

import Data.Char
import Control.Monad

main = do
  ns <- map digitToInt <$> getLine
  putStrLn $ solve ns operators

operators :: [(Int -> Int -> Int, Char)]
operators = [((+), '+'), ((-), '-')]

solve :: [Int] -> [(Int -> Int -> Int, Char)] -> String
solve [a, b, c, d] operators = (++"=7") . head $ do
  (op1, op1c) <- operators
  (op2, op2c) <- operators
  (op3, op3c) <- operators
  guard $ a `op1` b `op2` c `op3` d == 7
  return [intToDigit a, op1c, intToDigit b, op2c, intToDigit c, op3c, intToDigit d]