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 Ruby (2.3.3) (judge verdict: Accepted)

def calc(nums, pattern)
  n = nums.dup
  ret = n.dup.map(&:to_s)

  case pattern[0]
  when '+' then
    n[1] += n[0]
  when '-' then
    n[1] = n[0] - n[1]
  end

  case pattern[1]
  when '+' then
    n[2] += n[1]
  when '-' then
    n[2] = n[1] - n[2]
  end

  case pattern[2]
  when '+' then
    n[3] += n[2]
  when '-' then
    n[3] = n[2] - n[3]
  end

  if n[3] == 7
    ret[0] + pattern[0] + ret[1] + pattern[1] + ret[2] + pattern[2] + ret[3] + '=7'
  else
    nil
  end
end

n = gets.chars.map(&:to_i)

patterns = [
  ['+', '+', '+'],
  ['+', '+', '-'],
  ['+', '-', '+'],
  ['+', '-', '-'],
  ['-', '+', '+'],
  ['-', '+', '-'],
  ['-', '-', '+'],
  ['-', '-', '-']
]

patterns.each do |p|
  ans = calc(n, p)
  if !ans.nil?
    puts ans
    break
  end
end