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 <bits/stdc++.h>
using namespace std;
int main () {
  char A, B, C, D;
  cin >> A >> B >> C >> D;
  int num;
  vector<int> ans(3);
  for(int i = 0; i < 2; i++) {
    for(int j = 0; j < 2; j++) {
      for(int k = 0; k < 2; k++) {
        int num = A - '0';
        if (i == 0) num += B - '0';
        else num -= B - '0';
        if (j == 0) num += C - '0';
        else num -= C - '0';
        if (k == 0) num += D - '0';
        else num -= D - '0';
        if (num == 7) {
          ans.at(0) = i, ans.at(1) = j, ans.at(2) = k;
          break;
        }
      }
    }
  }
  vector<char> sub(3);
  for(int i = 0; i < 3; i++) {
    if(ans.at(i) == 0) sub.at(i) = '+';
    else sub.at(i) = '-';
  }
  cout << A << sub.at(0) << B << sub.at(1) << C << sub.at(2) << D << "=7" << endl;
  return 0;
}