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)

use std::io::{Read, stdin};
use std::str::FromStr;


fn main() {
    let abcd: i32 = read();
    let a = abcd / 1000;
    let b = (abcd - a * 1000) / 100;
    let c = (abcd - a * 1000 - b * 100) / 10;
    let d = abcd - a * 1000 - b * 100 - c * 10;
    let mut s = String::new();
    for i in 0..8 {
        let mut ans = a;
        if i % 2 == 0 { ans += b; } else { ans -= b; }
        let op2i = i / 2;
        if op2i % 2 == 0 { ans += c; } else { ans -= c; }
        let op3i = op2i / 2;
        if op3i % 2 == 0 { ans += d; } else { ans -= d; }
        if ans == 7 {
            s.push_str(a.to_string().as_ref());
            if i % 2 == 0 {s.push('+');} else { s.push('-'); }
            s.push_str(b.to_string().as_ref());
            if op2i % 2 == 0 {s.push('+');} else { s.push('-'); }
            s.push_str(c.to_string().as_ref());
            if op3i % 2 == 0 {s.push('+');} else { s.push('-'); }
            s.push_str(d.to_string().as_ref());
            s.push_str("=7");
            break;
        }
    }
    println!("{}", s);
}


fn read<T: FromStr>() -> T {
    let stdin = stdin();
    let stdin = stdin.lock();
    let token: String = stdin
        .bytes()
        .map(|c| c.expect("failed to read char") as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect();
    token.parse().ok().expect("failed to parse token")
}