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;
class Program{
	public static void Main(){
		string str = Console.ReadLine();
		double A = Char.GetNumericValue(str[0]);
		double B = Char.GetNumericValue(str[1]);
		double C = Char.GetNumericValue(str[2]);
		double D = Char.GetNumericValue(str[3]);
		double B2, C2, D2;
		int f = 0;
		for (int p = 0; p <= 1; p++ ){
			if (f == 1)
				break;
			for (int q = 0; q <= 1; q++ ){
				if (f == 1)
					break;
				for (int r = 0; r <= 1; r++ ){
					B2 = Math.Pow(-1,p) * B;
					C2 = Math.Pow(-1,q) * C;
					D2 = Math.Pow(-1,r) * D;
					if (A + B2 + C2 + D2 == 7){
						string B3 = (B2 >= 0) ? "+" + B : "-" + B;
						string C3 = (C2 >= 0) ? "+" + C : "-" + C;
						string D3 = (D2 >= 0) ? "+" + D : "-" + D;
						Console.WriteLine("{0}{1}{2}{3}=7",A,B3,C3,D3);
						f = 1;
						break;
					}
				}
			}
		}
	}
}