output_description: Print the formula you made, including the part `=7`.
  
  Use the signs `+` and `-`.
  
  Do not print a space between a digit and a sign.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      ABCD
attempt: a,b,c,d = map(lambda x: int(x), list(input()))
  
  cnt = 0
  def get_str(a):
      if a >= 0:
          s = "+{}".format(a)
      else:
          s = "{}".format(a)
      return s
  
  for i in range(1 << 4 - 1):
      if (i >> 3) % 2 == 0:
          a = -a
      if (i >> 2) % 2 == 0:
          b = -b
      if (i >> 1) % 2 == 0:
          c = -c
      if (i >> 0) % 2 == 0:
          d = -d
  
      if a + b + c + d  == 7:
          s = ""
          s += get_str(a)
          s += get_str(b)
          s += get_str(c)
          s += get_str(d)
          s += "=7"
          if a >= 0:
              print(s[1::])
          else:
  
problem_description: 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.
samples: [{"input": "1222", "output": "1+2+2+2=7\n    \n\nThis is the only valid solution.\n\n* * *"}, {"input": "0290", "output": "0-2+9+0=7\n    \n\n0 - 2 + 9 - 0 = 7 is also a valid solution.\n\n* * *"}, {"input": "3242", "output": "3+2+4-2=7"}]