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 Kotlin (1.0.0) (judge verdict: Wrong Answer)

import kotlin.system.exitProcess

fun main(args: Array<String>) {
    val input = readLine()!!
    var numbers = mutableListOf<Int>()
    for (i in 0..input.length - 1){
        numbers.add(Integer.parseInt(input[i].toString()))
    }
    solve(1, numbers, numbers[0], "${numbers[0]}")
}

fun solve(index: Int, numbers: List<Int>, answer: Int, expr: String) {
    when {
        answer == 7 -> {
            println("$expr=7")
            exitProcess(0)
        }
        index == numbers.size -> return
        else -> {
            solve(index + 1, numbers, answer + numbers[index], "$expr+${numbers[index]}")
            solve(index + 1, numbers, answer - numbers[index], "$expr-${numbers[index]}")
        }
    }
}