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: Wrong Answer)


#[allow(dead_code)]
const MOD: usize = 1_000000000 + 7;

fn main() {
    let mut cin = Scanner::new();
    let n = cin.next_isize();

    for i in 0..1<<3 {
        let mut v = n / 1000;
        let mut k = 1;
        for j in 0..3 {
            let sign = (i>>j&1)*2-1;
            v += sign * (n / k % 10);
            k *= 10
        }
        let mut k = 1;
        if v == 7 {
            print!("{}", n / 1000);
            for j in 0..3 {
                let sign = if (i>>j&1) == 0 { '-' } else { '+' };
                print!("{}{}", sign, n / k % 10);
                k *= 10
            }
            print!("=7");
            return;
        }
    }
}


struct Scanner {
    reader: std::io::Stdin,
    tokens: std::collections::VecDeque<String>,
}

impl Scanner {
    fn new() -> Self {
        Scanner {
            reader: std::io::stdin(),
            tokens: std::collections::VecDeque::new(),
        }
    }

    fn next(&mut self) -> String {
        if self.tokens.is_empty() {
            let mut s = String::new();
            loop {
                self.reader.read_line(&mut s).ok();
                let s = s.trim();
                if s.len() != 0 {
                    for it in s.split_whitespace() {
                        self.tokens.push_back(it.into())
                    }
                    break;
                }
            }
        }
        self.tokens.pop_front().unwrap()
    }

    fn next_generics<T>(&mut self) -> T where
        T: std::str::FromStr + std::marker::Copy,
        <T as std::str::FromStr>::Err: std::fmt::Debug
    {
        self.next().parse().unwrap()
    }
    
    #[allow(dead_code)] fn next_i32(&mut self) -> i32 { self.next_generics::<i32>() }
    #[allow(dead_code)] fn next_i64(&mut self) -> i64 { self.next_generics::<i64>() }
    #[allow(dead_code)] fn next_u64(&mut self) -> u64 { self.next_generics::<u64>() }
    #[allow(dead_code)] fn next_usize(&mut self) -> usize { self.next_generics::<usize>() }
    #[allow(dead_code)] fn next_isize(&mut self) -> isize { self.next_generics::<isize>() }
}