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;
using System.IO;

namespace AtCoder
{
    class Program
    {
        static void Main(string[] args)
        {
            //[summary]C - Train Ticket

            //4つの数字を取得
            var numbers = GetSourceNumbers().ToList();

            string formula = GetFormulaToBeSeven(numbers);
            Console.WriteLine(formula);
        }

        static IEnumerable<int> GetSourceNumbers()
        {
            string line = Console.ReadLine().TrimEnd();

            foreach(var c in line)
            {
                yield return int.Parse(c.ToString());
            }
        }

        static string GetFormulaToBeSeven(List<int> numbers)
        {
            var variations = new string[8] 
            {
                "+++", "++-", "+-+", "+--", "-++", "-+-", "--+", "---"
            };

            foreach(var s in variations)
            {
                int sum = numbers[0];

                for(int i = 0; i < 3; i++)
                {
                    if (s[i] == '+')
                    {
                        sum += numbers[i + 1];
                    }
                    else
                    {
                        sum -= numbers[i + 1];
                    }
                }

                if (sum == 7)
                {
                    string formula = "";

                    for(int i = 0; i < 3; i++)
                    {
                        formula += numbers[i] + s[i].ToString();
                    }

                    formula += numbers[3] + "=7";
                    return formula;
                }
            }

            return null;
        }
    }
}