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.CodeDom.Compiler;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;
using System.Xml;

class Program
{
	static void Main(string[] args)
	{
		string s = Console.ReadLine();
		int A = int.Parse(s.Substring(0, 1));
		int B = int.Parse(s.Substring(1, 1));
		int C = int.Parse(s.Substring(2, 1));
		int D = int.Parse(s.Substring(3, 1));
		string op1 = "";
		string op2 = "";
		string op3 = "";
		string ans = "=7";

		for(int i = 0;i < 2; i++)
		{
            int sumAB = 0;
			check(i, B, A, out sumAB, out op1);
			for (int j = 0; j < 2; j++)
			{
                 int sumABC = 0;
				check(j, C, sumAB, out sumABC, out op2);
				for (int k = 0; k < 2; k++)
				{
                     int sumABCD = 0;
					check(k, D, sumABC, out sumABCD, out op3);
					if(sumABCD == 7)
					{
						Console.WriteLine(A+op1+B+op2+C+op3+D+ans);
						break;
					}
				}
			}
		}
	}

	static void check(int flg,int num ,int oldsum ,out int newsum,out string op)
	{
		if(flg == 0)
		{
			newsum = oldsum + num;
			op = "+";
		}
		else
		{
			newsum = oldsum - num;
			op = "-";
		}
	}
}

//string s = Console.ReadLine();
//int[] intArray = Console.ReadLine().Split(' ').Select(i => int.Parse(i)).ToArray();
//int H = intArray[0];
//int W = intArray[1];
//int N = int.Parse(Console.ReadLine());
//List<int> A = new List<int>(Console.ReadLine().Split(' ').Select(i => int.Parse(i)).ToArray());
//Boolean ok = false;

//Console.WriteLine(ans);
//Console.WriteLine("Yes");
//Console.WriteLine("No");
//Console.ReadKey();

//string[] strArray = Console.ReadLine().Split(' ').ToArray();
//string S = strArray[0];
//string T = strArray[1];