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 s = read::<String>();
    let mut nums: Vec<i32> = Vec::new();
    for c in s.chars() {
        nums.push(c as i32 - 48);
    }
    let n = nums.len();

    for bit in 0..(1 << n - 1) {
        let mut ret = nums[0];
        let mut ops: Vec<&str> = Vec::new();
        for i in 0..n-1 {
            if (bit & (1 << i)) != 0 {
                ret += nums[i + 1];
                ops.push("+");
            } else {
                ret -= nums[i + 1];
                ops.push("-");
            }
        }

        if ret == 7 {
            println!("{}{}{}{}{}{}{}=7", nums[0], ops[0], nums[1], ops[1], nums[2], ops[2], nums[3]);
            return
        }
    }
}

fn read<T: std::str::FromStr>() -> T {
    let mut s = String::new();
    std::io::stdin().read_line(&mut s).unwrap();
    s.trim().parse().ok().unwrap()
}