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 Rust (1.15.1) (judge verdict: Accepted)

fn main() {
    let stdin = std::io::stdin();
    let mut buf = String::new();
    stdin.read_line(&mut buf).unwrap();
    let v: Vec<i32> = buf.trim().chars().map(|c| c.to_digit(10).unwrap() as i32).collect();

    let mut v2: Vec<char> = Vec::new();
    for bit in 0..(1<<3) {
        let mut res = v[0];
        v2.clear();
        for i in 0..3 {
            if bit & (1<<i) == 0 {
                res += v[i + 1];
                v2.push('+');
            } else {
                res -= v[i + 1];
                v2.push('-');
            }
        }
        if res == 7 {
            break;
        }
    }

    println!("{}{}{}{}{}{}{}=7", v[0], v2[0], v[1], v2[1], v[2], v2[2], v[3]);
}