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 OCaml (4.10.0) (judge verdict: Accepted)

let words = Str.split (Str.regexp " ")
let chars s = List.init (String.length s) (String.get s)
let (>>) f g x = g (f x)

let [a; b; c; d] = read_line () |> chars |> List.map (Char.escaped >> int_of_string)

let ans =
  let rec solve bits =
    let sign = List.init 3 (fun i -> if bits land (1 lsl i) <> 0 then 1 else -1) in
    let x =
      List.combine sign [b; c; d]
      |> List.fold_left (fun acc pair -> acc + fst pair * snd pair) a
    in
    if x = 7 then bits else solve (bits + 1)
  in solve 0

let () =
  print_int a;
  print_string (if ans land 1 <> 0 then "+" else "-");
  print_int b;
  print_string (if ans land 2 <> 0 then "+" else "-");
  print_int c;
  print_string (if ans land 4 <> 0 then "+" else "-");
  print_int d;
  print_string "=7";
  print_newline ()