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(lhs, op, rhs)
  # opが0なら加算
  if op == 0
    lhs + rhs
  else
    lhs - rhs
  end
end

def to_op(bit)
  if bit == 0
    '+'
  else
    '-'
  end
end

BIT_NUM = 3

def main
  nums = ARGF.gets.chars.map(&:to_i)

  # bit mask の生成
  0.upto((1 << BIT_NUM) - 1) do |mask|

    a = nums[0]
    # 各bitを下から舐める
    0.upto(BIT_NUM - 1)  do |i|
      # 加算 or 減算
      a = calc(a, mask[i], nums[i+1])
    end

    if a == 7
      puts "#{nums[0]}#{to_op(mask[0])}#{nums[1]}#{to_op(mask[1])}#{nums[2]}#{to_op(mask[2])}#{nums[3]}=7"
      return
    end
  end

  puts 'error'  # 問題の前提上、ありえない
end

if __FILE__ == $0
  main
end