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: Wrong Answer)

#include <bits/stdc++.h>
using namespace std;
int main()
{
	string x;
	cin >> x;
	int sum = 0;
	for (int i = 0; i < x.size(); i++)
	{
		sum += x[i] - '0';
	}
	if (sum == 7)
	{
		for (int i = 0; i < x.size() - 1; i++)
			cout << x[i] << "+";
		cout << x[x.size() - 1];
	}
	else
	{
		sum = sum - 7;
		sum=(sum+1)/2;
		int sum1 = sum;
		vector<char>v;
		bool flag = 0;
		for (int i = 0; i < x.size(); i++)
		{
			if (x[i] - '0' == sum)
			{
				flag = 1;
				v.push_back(x[i]);
				break;
			}
		}
		if (!flag)
		{
			for (int i = 0; i < x.size(); i++)
			{
				for (int j = 0; j < x.size(); j++)
				{
					if ((x[i] - '0') + (x[j] - '0') == sum&&i!=j)
					{
						v.push_back(x[i]);
						v.push_back(x[j]);
						flag = 1;
						break;
					}
				}
			}
		}
		if (!flag)
		{
			for (int i = 0; i < x.size(); i++)
			{
				for (int j = 0; j < x.size(); j++)
				{
					for (int h = 0; h < x.size(); h++)
					{
						if (i != j&&i != h&&j != h && (x[i] - '0') + (x[j] - '0') + (x[h] - '0') == sum)
						{
							v.push_back(x[i]);
							v.push_back(x[j]);
							v.push_back(x[h]);
						}
					}
				}
			}
		}
		for (int i = 0; i < x.size(); i++)
		{
			if (find(v.begin(), v.end(), x[i]) != v.end())
			{
				cout << '-' << x[i];
				v[find(v.begin(), v.end(), x[i])-v.begin()] = '-';
			}
			else
			{
				if (i)
					cout <<"+" <<x[i];
				else
					cout  << x[i];
			}
		}
	}
	cout << "=7";
	return 0;
}