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 JavaScript (node.js v5.12) (judge verdict: Accepted)

'use strict'

function main(input){
  const lines = input.split('\n');

  const ABCD = lines.shift().split('').map(x => parseInt(x));
  const A = ABCD[0];
  const B = ABCD[1];
  const C = ABCD[2];
  const D = ABCD[3];

  for(var i=0;i<8;i++){
    let operators = (8+i).toString(2).split('').map(function(x){if(x=='1'){return '+'}else{return '-'}}).slice(1,4)
    let seven = A;
    for(let j=0;j<3;j++){
      if(operators[j]=='+'){
        seven += ABCD[j+1]
      }else{
        seven += -1 *  ABCD[j+1]
      }
    }
    if(seven==7){
      let result = `${A}${operators[0]}${B}${operators[1]}${C}${operators[2]}${D}=7`;
      console.log(result);  

      return
    }
  }
}

main(require('fs').readFileSync('/dev/stdin', 'utf8'));