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.Diagnostics;
using System.Linq;

namespace AtCoder.C
{
    public class Program
    {
        public static void Main() { var r = GetResult(); Debug.WriteLine(r); Console.Write(r); }

        private static object GetResult()
        {
            var ABCD = ReadText();
            var A = int.Parse(ABCD[0].ToString());
            var B = int.Parse(ABCD[1].ToString());
            var C = int.Parse(ABCD[2].ToString());
            var D = int.Parse(ABCD[3].ToString());

            for (int i = 0; i < 2; i++)
            {
                for (int j = 0; j < 2; j++)
                {
                    for (int k = 0; k < 2; k++)
                    {
                        var ans = A;
                        if (i == 0)
                        {
                            ans += B;
                        }
                        else
                        {
                            ans -= B;
                        }
                        if (j == 0)
                        {
                            ans += C;
                        }
                        else
                        {
                            ans -= C;
                        }
                        if (k == 0)
                        {
                            ans += D;
                        }
                        else
                        {
                            ans -= D;
                        }
                        if (ans == 7)
                        {
                            return
                                A + (i == 0 ? "+" : "-") +
                                B + (j == 0 ? "+" : "-") +
                                C + (k == 0 ? "+" : "-") +
                                D + "=7";
                        }
                    }
                }
            }

            return null;
        }

        #region Console

        public static string ReadText() { return Console.ReadLine(); }
        public static List<string> ReadTexts() { return Console.ReadLine().Split(' ').ToList(); }
        public static long ReadLong() { return long.Parse(Console.ReadLine()); }
        public static List<long> ReadLongs() { return Console.ReadLine().Split(' ').Select(x => long.Parse(x)).ToList(); }

        #endregion
    }
}