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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include <iostream>
#include <string>
using namespace std;
char plusminus(int a) {
	if (a == 1) {
		return '+';
	}
	else {
		return '-';
	}
}

int main() {
	int pattern[3][8] = {
		{-1,-1,-1,-1,1,1,1,1},
		{-1,-1,1,1,-1,-1,1,1},
		{-1,1,-1,1,-1,1,-1,1} 
	};
	int num[4];
	int X = 7;
	int ans = 0;
	string s;

	cin >> s;

	for (int i = 0; i < 4; i++)
	{
		num[i] = s[i] - '0';
	}

	for ( ans = 0; ans < 8; ans++)
	{
		int tmp = num[0];
		
		for (int i = 0; i < 3; i++)
		{
			tmp += pattern[i][ans] * num[i + 1];
		}

		if (tmp == X) {
			break;
		}
	}

	cout << num[0];
	for (int i = 0; i < 3; i++)
	{
		cout << plusminus(pattern[i][ans]) << num[i + 1];
	}
	cout << "=" << X << endl;

	return 0;
}