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;

vector<string>s;

int decide(int x, int y, char s){
    if(s=='-')
        return x-y;
    return x+y;
}

void calculate(){
    string sign = "+++";

    for(int i=1; i<=4; i++){
        do{
            s.push_back(sign);
        }while(next_permutation(sign.begin(), sign.end()));

        for(int j=2, k=0;k<i; k++,j--)
            sign[j] = '-';
    }
}

int main(){
    calculate();
    string num;

    while(cin>>num){
        string ans;
        for(int i=0; i<s.size(); i++){
            int sum = num[0]-'0';

            for(int j=0; j<3; j++){
                sum = decide(sum, num[j+1]-'0', s[i][j]);
            }

            if(sum == 7)
                ans = s[i];
        }

        for(int i=0; i<3; i++)
            printf("%c%c",num[i],ans[i]);
        printf("%c\n",num[3]);
    }

    return 0;
}