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

fn read_vec<T: std::str::FromStr>() -> Vec<T> {
    read::<String>()
        .split_whitespace()
        .map(|e| e.parse().ok().unwrap())
        .collect()
}

fn read_vec2<T: std::str::FromStr>(n: u32) -> Vec<Vec<T>> {
    (0..n).map(|_| read_vec()).collect()
}

fn main() {
    let input:String = read();
    let v: Vec<i32> = input.chars().map(|x| x.to_digit(10).unwrap() as i32).collect();
    let ans = match (v[0],v[1],v[2],v[3]) {
        (a,b,c,d) if a + b + c + d  == 7 => format!("{}+{}+{}+{}",a,b,c,d),
        (a,b,c,d) if a + b - c + d  == 7 => format!("{}+{}-{}+{}",a,b,c,d),
        (a,b,c,d) if a + b + c - d  == 7 => format!("{}+{}+{}-{}",a,b,c,d),
        (a,b,c,d) if a + b - c - d  == 7 => format!("{}+{}-{}-{}",a,b,c,d),
        (a,b,c,d) if a - b + c + d  == 7 => format!("{}-{}+{}+{}",a,b,c,d),
        (a,b,c,d) if a - b - c + d  == 7 => format!("{}-{}-{}+{}",a,b,c,d),
        (a,b,c,d) if a - b + c - d  == 7 => format!("{}-{}+{}-{}",a,b,c,d),
        (a,b,c,d) if a - b - c - d  == 7 => format!("{}-{}+{}+{}",a,b,c,d),
        _ =>  unreachable!(), 
    };
    println!("{}=7",ans);
}