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 C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;
using System.Linq;
using System.Collections.Generic;

class Cmondai
{
    static void Main()
    {
        var line = Console.ReadLine().ToCharArray().Select(x=>Int32.Parse(x.ToString())).ToArray();
        var A = line[0];
        var B = line[1];
        var C = line[2];
        var D = line[3];
        var count = Math.Pow(2, 4);
        for(int i = 0; i < count; ++i)
        {
            var isPlus = new bool[4];
            for (int j = 0; j < 4; ++j) isPlus[j] = ((1 & i >> j) == 1);
            var a = isPlus[0] ? A : A * (-1);
            var b = isPlus[1] ? B : B * (-1);
            var c = isPlus[2] ? C : C * (-1);
            var d = isPlus[3] ? D : D * (-1);
            if (a + b + c + d == 7)
            {
                var strA = isPlus[0] ? $"{A}" : $"-{A}";
                var strB = isPlus[1] ? $"+{B}" : $"-{B}";
                var strC = isPlus[2] ? $"+{C}" : $"-{C}";
                var strD = isPlus[3] ? $"+{D}" : $"-{D}";
                Console.WriteLine($"{strA}{strB}{strC}{strD}=7");
                return;
            }
        }
    }
}