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: Accepted)

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

public class Prog
{
    public static void Main()
    {
        string input = Console.ReadLine();
        string output = "";
        int all = int.Parse(input);
        int a = all / 1000;
        int b = (all - 1000 * a) / 100;
        int c = (all - 1000 * a - 100 * b) / 10;
        int d = all % 10;
        int[] y = new int[4];
        y[0] = a;
        y[1] = b;
        y[2] = c;
        y[3] = d;
        for(int i = 0; i < 8; i++)
        {
            int sum = a;
            output = input;
            string x = Convert.ToString(i, 2).PadLeft(3,'0');
            for (int j = 2; j >= 0; j--)
            {
                if (x[j] == '1')
                {
                    output = output.Insert(j + 1, "+");
                    sum = sum + y[j + 1];
                }
                else
                {
                    output = output.Insert(j + 1, "-");
                    sum = sum - y[j + 1];
                }
            }
            if(sum == 7)
            {
                output = output + "=7";
                Console.WriteLine(output);
                break;
            }
        }
    }
}