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 12.16.1) (judge verdict: Wrong Answer)

/**
 * bit全探索
 */
function Main(input){
    let Numarr = input.split('');
    let answer = '';
    const DFS = (numarr, str, num) => {
        const thisNum = numarr[0];
        if(thisNum == null && num === 7) return answer = str + '=7';
        if(thisNum == null) return;
        DFS(numarr.slice(1), str + '+' + thisNum, num + Number(thisNum))
        DFS(numarr.slice(1), str + '-' + thisNum, num - Number(thisNum))
        return
    }
    const n = Number(Numarr.shift())
    DFS(Numarr ,n,n)
    console.log(answer);
}
Main(require("fs").readFileSync("/dev/stdin", "utf8"));