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 solve(a: String) -> String {
    let d = a
        .chars()
        .map(|x| x.to_digit(10).unwrap() as i32)
        .collect::<Vec<_>>();
    let a = a.chars().collect::<Vec<_>>();
    let mut v = vec![];
    for i in 0..8 {
        let mut s = d[0];
        for j in 0..3 {
            if (i >> j) & 1 == 0 {
                s += d[j + 1];
            } else {
                s -= d[j + 1];
            }
        }
        v.push(s);
    }
    for (i, &x) in v.iter().enumerate() {
        if x == 7 {
            let mut s = String::new();
            s.push(a[0]);
            for j in 0..3 {
                if (i >> j) & 1 == 0 {
                    s.push('+');
                } else {
                    s.push('-');
                }
                s.push(a[j + 1]);
            }
            s.push_str("=7");
            return s;
        }
    }
    unreachable!();
}

fn main() {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).ok();
    let a = s.trim().to_string();
    let ans = solve(a);
    println!("{}", ans);
}