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: 
  def a(s,i):
      if i = l-1:
          if eval(s)==7:
              return s+"=7"
          return
      a(s+"+"+N[i],i+1)
      a(s+"-"+N[i],i+1)
  
  N = input()
  l = len(N)
  
  
  print(a(N[0],0)
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"}]