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.Text;
using System.Collections.Generic;
using System.Linq;
 
class Program {
    static void Main(string[] args) {
        var input = Console.ReadLine();
        string[] S = new string[input.Length];
        for(int i = 0;i < input.Length ;i++){
            S[i] = input[i].ToString();
        }
        LowerBound(S);
    }
    
    public static void LowerBound(string[] S) {
        var N = S.Length;
        for(int i = 0;i < Math.Pow(2,N-1);i++){
            var res = int.Parse(S[0]);
            var ans = S[0];
            for(int j = 1;j <　N ;j++){
                int bit = (int) Math.Pow(2,j-1);
                if((i&bit) != 0){
                    res += int.Parse(S[j]);
                ans = String.Concat(ans,String.Concat("+",S[j]));
                }else{
                    res -= int.Parse(S[j]);
                    ans = String.Concat(ans,String.Concat("-",S[j]));
                }
            }
            if(res == 7){
                Console.WriteLine(ans+"=7");
                break;
            }
        }
         }
             
     }