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;

fn read_line() -> String{
    let mut s = String::new();
    io::stdin().read_line(&mut s).unwrap();
    s
}

// https://abc079.contest.atcoder.jp/tasks/abc079_a

fn main(){
    let line = read_line();
//    let split : Vec<&str> = line.trim().split(' ').collect();
    let split = line.trim().chars();
    let array : Vec<i32> = split.into_iter().map(|c| c.to_string().parse().unwrap()).collect();

    for i in 0..8{
        let mut sum = array[0];
        let mut output = String::new();

        output = format!("{}",array[0]);

        for j in 1..4{
            let mask = 1 << (j-1);
            let sign = if mask & i == 0 { 1 }else{ -1};
            let op = if sign == 1 {'+'}else{'-'};
            sum += sign * array[j];

            output = format!("{}{}{}",output,op,array[j]);
        }

        if sum == 7{
            println!("{}=7",output);
            break;
        }
    }

}