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<vector>
#include<string>
#include<algorithm>
using namespace std;

bool check (string s){
  int n = s.length();
  if (n%2==1){
    return false;
  }
  else {
    return (s.substr(0,n/2-1)==s.substr(n/2));
  }
}

int choise_sort (int n, int a[]){
  int index;
  for (int i=0; i<n-1; i++){
    int min = a[i], num;
    for (int j=i; j<n-1; j++){
      if (a[j+1]<min){
        min = a[j+1];
        num = j+1;
      }
    }
    index = a[i];
    a[i] = min;
    a[num] = index;
  }
}

int main(){
  int x,a,b,c,d;
  cin >> x;

  d = x%10;
  x /= 10;
  c = x%10;
  x /= 10;
  b = x%10;
  x /= 10;
  a = x%10;

  for (int i=-1; i<2; i+=2){
    for(int j=-1; j<2; j+=2){
      for (int k=-1; k<2; k+=2){
        int ans = a+(b*(-1*i))+(c*(-1*j))+(d*(-1*k));
        if (ans==7){
          cout << a;
          if (-1*i>=0) cout << "+";
          else cout << "-";
          cout << b;
          if (-1*j>=0) cout << "+";
          else cout << "-";
          cout << c;
          if (-1*k>=0) cout << "+";
          else cout << "-";
          cout << d;
          cout << "=7" << endl;
          return 0;
        }
      }
    }
  }
}