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)

#[macro_use]
mod input {

use std;
use std::io;

const SPLIT_DELIMITER: char = ' ';

/// 空白で区切られた複数の値の読み込む。
/// # Example
/// ```ignore
/// use cp_template::*;
///
/// let (a,b):(usize,usize);
/// input!(a,b);
/// ```
#[macro_export]
#[allow(unused_macros)]
macro_rules! input {
    ( $($x:expr ),*) => {
        {
            let temp_str = input_line_str();
            let mut split_result_iter = temp_str.split_whitespace();
                $(
                let buf_split_result = split_result_iter.next();
                let buf_split_result = buf_split_result.unwrap();
                    ($x) = buf_split_result.parse().unwrap();
                )*
        }
    };
}

/// 文字列を一行読み込む
/// # Example
/// ```ignore
/// use cp_template::*;
///
/// let s = input_line_str();
/// ```
#[allow(dead_code)]
pub fn input_line_str() -> String {
    let mut s = String::new();
    io::stdin().read_line(&mut s).unwrap();
    s.trim().to_string()
}

/// 一つの変数を出力する。
/// ```
/// use cp_template::*;
///
/// let a=100;
/// p(a);
/// //上と下は等価です。
/// println!("{}",a);
/// ```
#[allow(dead_code)]
pub fn p<T>(t: T)
where
    T: std::fmt::Display,
{
    println!("{}", t);
}

/// 指定した行数を読み込み、二次元配列に変換する。
/// # Examples
/// ```ignore
/// use cp_template::*;
///
/// //10行読み込む。
/// let v = input_vector2d::<usize>(10);
/// ```
#[allow(dead_code)]
pub fn input_vector2d<T>(line: usize) -> Vec<Vec<T>>
where
    T: std::str::FromStr,
{
    let mut v: Vec<Vec<T>> = Vec::new();

    for _ in 0..line {
        let vec_line = input_vector();
        v.push(vec_line);
    }
    v
}

/// 一行読み込み、配列(Vec)に変換する。
/// # Examples
/// ```ignore
/// use cp_template::*;
///
/// let v=input_vector::<usize>();
/// ```
#[allow(dead_code)]
pub fn input_vector<T>() -> Vec<T>
where
    T: std::str::FromStr,
{
    let mut v: Vec<T> = Vec::new();

    let s = input_line_str();
    let split_result = s.split(SPLIT_DELIMITER);
    for z in split_result {
        let buf = match z.parse() {
            Ok(r) => r,
            Err(_) => panic!("Parse Error"),
        };
        v.push(buf);
    }
    v
}

/// String(str)を配列(Vec<char>)に変換する。
/// # Examples
/// ```ignore
/// use cp_template::*;
///
/// let s = String::from("abc");
/// let v = str2vec(&s);
/// let v = str2vec(&input_line_str());
/// ```
#[allow(dead_code)]
pub fn str2vec(s: &str) -> Vec<char> {
    let mut v: Vec<char> = Vec::new();
    for c in s.chars() {
        v.push(c);
    }
    v
}

}

#[allow(unused_imports)]
use input::*;

fn main() {
    let s = str2vec(&input_line_str());
    let mut v: Vec<isize> = Vec::new();
    for z in s {
        v.push(z.to_string().parse().unwrap());
    }
    let mut count = 0;
    let mut ans;
    for z in 0..8 {
        ans = v[0];
        count = z;
        if (z & 0b100) != 0 {
            ans += v[1];
        } else {
            ans -= v[1];
        }
        if (z & 0b010) != 0 {
            ans += v[2];
        } else {
            ans -= v[2];
        }
        if (z & 0b001) != 0 {
            ans += v[3];
        } else {
            ans -= v[3];
        }
        if ans == 7 {
            break;
        }
    }

    print!("{}", v[0]);
    if (count & 0b100) != 0 {
        print!("+");
    } else {
        print!("-");
    }
    print!("{}", v[1]);
    if (count & 0b010) != 0 {
        print!("+");
    } else {
        print!("-");
    }
    print!("{}", v[2]);
    if (count & 0b001) != 0 {
        print!("+");
    } else {
        print!("-");
    }
    println!("{}=7", v[3]);
}