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 Ruby (2.3.3) (judge verdict: Accepted)

$inputs = '1222'.split('').map(&:to_i)
$target = 7

def prepare
    $inputs = STDIN.gets.chomp.split('').map(&:to_i)
end

def dfs(depth, value, form)
    if depth == $inputs.count
        if value == $target
            return true, form + '=' + $target.to_s
        else
            return false, form
        end
    end

    result1, form1 = dfs depth + 1, value + $inputs[depth],
        (depth > 0 ? form + '+' : '') + $inputs[depth].to_s
    if result1 == true
        return result1, form1
    end

    result2, form2 = dfs depth + 1, value - $inputs[depth],
        (depth > 0 ? form + '-' : '') + $inputs[depth].to_s
    if result2 == true
        return result2, form2
    end

    return false, ''
end

def solve
    result, form = dfs 0, 0, ''
    if result == true
        puts form
    end
end

prepare
solve