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 (4.02.3) (judge verdict: Accepted)

let id x = x
let n = Scanf.scanf "%s\n" id
let a = (int_of_char n.[0]) - 48
let b = (int_of_char n.[1]) - 48
let c = (int_of_char n.[2]) - 48
let d = (int_of_char n.[3]) - 48
let oplist = [1;0]

let i2op i = if i = 1 then (+) else (-)
let i2c i = if i = 1 then '+' else '-'
  
let rec loop3 op1 op2 l =
  match l with
  | [] -> []
  | op3 :: rest ->
     if (i2op op3) ((i2op op2) ((i2op op1) a b) c) d = 7 then (op1,op2,op3) :: loop3 op1 op2 rest
       else loop3 op1 op2 rest

let rec loop2 op1 l =
  match l with
  | [] -> []
  | op2 :: rest -> (loop3 op1 op2 oplist) @ loop2 op1 rest
     
let rec loop1 l =
  match l with
  | [] -> []
  | op1 :: rest -> (loop2 op1 oplist) @ loop1 rest
    
let (op1,op2,op3) = List.hd (loop1 oplist)
let (op1,op2,op3) = (i2c op1,i2c op2,i2c op3)
  
let () =
  Printf.printf "%d%c%d%c%d%c%d=7\n" a op1 b op2 c op3 d