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 Scala (2.11.7) (judge verdict: Accepted)

object Main {

  def main(args: Array[String]): Unit = {
    import scala.io.StdIn._

    val abcd = readLine().map(_.toString.toInt).toList

    var result: String = abcd.head.toString
    // 見つかったら終了
    def dfs(lst: List[Int], r: Int, res: String): Boolean =
      if (lst.isEmpty) {
        if (r == 7) {
          result += res + "=7"
          true
        } else false
      } else
        dfs(lst.tail, r + lst.head, res + "+" + lst.head) ||
          dfs(lst.tail, r - lst.head, res + "-" + lst.head)

    dfs(abcd.tail, abcd.head, "")
    println(result)
  }

}