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.Text;
using System.Threading.Tasks;

namespace ManyFunctions
{
	public static class Program
	{
		public static void Main(string[] args)
		{
			var s = Console.ReadLine();

			Console.WriteLine(ManyFunctions(s, ""));
		}

		public static string ManyFunctions(string s, string sp)
		{
			if(s.Length == 1) {
				sp += s;
				var sum = int.Parse(sp[0].ToString());
				var isPlus = false;

				foreach (var c in sp.Remove(0, 1)) {
					switch (c) {
						case '+':
							isPlus = true;
							break;
						case '-':
							isPlus = false;
							break;
						default:
							var x = int.Parse(c.ToString());
							if (isPlus) {
								sum += x;
							} else {
								sum -= x;
							}
							break;
					}
				}

				return sum == 7 ? sp + "=7" : "";
			}

			sp += s[0].ToString();
			s = s.Remove(0, 1);

			//+
			var ret = ManyFunctions(s, sp + "+");

			if(ret != "") {
				return ret;
			}

			//-
			ret = ManyFunctions(s, sp + "-");

			if (ret != "") {
				return ret;
			}

			return "";
		}
	}
}