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 <map>
#include <vector>
#include <cmath>
#include <string>
#include <cstring>
#include <algorithm>
#include <climits>
#include <stack>
#include <queue>
#include <set>
#include <cctype>
#include <bitset>
#include <type_traits>

#include <list>
using namespace std;

#define REP(i, n) for (int i = 0; i < (n); ++i)
#define rep(i, a, b) for (int i = a; i < (b); ++i)
#define YES(j) cout << (j ? "YES" : "NO") << endl;
#define Yes(j) std::cout << (j ? "Yes" : "No") << endl;
#define yes(j) std::cout << (j ? "yes" : "no") << endl;

string s;
int a[10];
bool flag = false;

void dfs(int pos, int sum, string ans)
{
    if (pos == 4)
    {
        if (sum == 7 && !flag)
        {
            cout << ans + "=7" << endl;
            flag = true;
        }
    }
    else
    {
        if (pos == 0)
        {
            dfs(pos + 1, sum + a[pos], ans + s[pos]);
        }
        else
        {
            dfs(pos + 1, sum + a[pos], ans + "+" + s[pos]);
            dfs(pos + 1, sum - a[pos], ans + "-" + s[pos]);
        }
    }
}

int main(void)
{
    cin >> s;
    REP(i, 4)
    {
        a[i] = s[i] - '0';
        //cout << a[i] << endl;
    }
    dfs(0, 0, "");
}