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 <iostream>
#include <string>

using namespace std;

int main() {
  int input;
  cin >> input;
  int nums[4];
  nums[0] = input / 1000;
  nums[1] = input / 100;
  nums[2] = input / 10;
  nums[3] = input / 1;
  int sum = nums[0];
  string str = "";
  int strategy = 0;
  for(int i = 0; i < 3; i++) {
    for(int j = 0; j < 2; j++) {
      if(j == 0) {
        strategy = strategy & 1 << i;
      } 
    }
    if(i == 2) {
      int sum = nums[0];
      string ans = "";
      ans += to_string(nums[0]);
      for(int k = 0; k < 3; k++) {
        if(strategy >> k & 1) {
          sum += nums[k+1];
          ans += "+"; 
        } else {
          sum -= nums[k+1];
          ans += "-";
        }
        ans += to_string(nums[k + 1]);
      }
      if (sum == 7) {
        cout << ans << "=7" << endl;
        return 0;
      }
      strategy = 0;
    }
    
  }
}