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>

using namespace std;

int main() {
  string s;
  char op[4];
  cin >> s;
  int a,b,c,d;
  // cout << "s:" << s << endl;
  for (int bit = 0; bit < (1<<3); bit++) {
    // cout << bitset<4>(bit) << endl;
    int sum = s[0] - '0';
    for (int i = 0; i < 3; i++) {
      if (bit & (1<<i)) {
        // cout << i << ":on" << endl;
        sum += (s[i+1] - '0');
        op[i] = '+';
      } else {
        // cout << i << ":off" << endl;
        sum -= (s[i+1] - '0');
        op[i] = '-';
      }
      // cout << "i:" << i << "," << s[i+1] << ", sum:" << sum << endl;
    }
    if (sum == 7) {
      cout << s[0] << op[0] << s[1] << op[1] << s[2] << op[2] << s[3] << op[3] << s[4] << "=7" << endl;
      return 0;
    }
  }
}