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 (2.13.1) (judge verdict: Accepted)

object Main extends App {
  def calc(i: Int, c: Char, j: Int): Int = if (c == '+') i + j else i - j

  def duplicatePermutation[A](list: List[A], length: Int): List[List[A]] = {
    if (length == 1) {
      list.map(List(_))
    } else {
      list.flatMap(x => duplicatePermutation(list, length - 1).map(y => x :: y))
    }
  }

  val sc = new java.util.Scanner(System.in)
  val Array(a, b, c, d) = sc.next().toCharArray.map(_.toString)
  duplicatePermutation(List('+', '-'), 3).collectFirst {
    case Seq(ab, bc, cd) if calc(calc(calc(a.toInt, ab, b.toInt), bc, c.toInt), cd, d.toInt) == 7 =>
      Array(a, ab.toString, b, bc.toString, c, cd.toString, d, "=", "7").mkString
  }.foreach(println)
}