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: from math import ceil
  
  
  def dfs(i, sum, count, residue):
      global ans
      if i == d:
          if sum < g:
              use = max(residue)
              n = min(pc[use - 1][0], ceil((g - sum) / (use * 100)))
              count += n
              sum += n * use * 100
  
          if g <= sum:
              ans = min(ans, count)
  
      else:
          dfs(i + 1, sum, count, residue)
          dfs(
              i + 1,
              sum + pc[i][0] * (i + 1) * 100 + pc[i][1],
              count + pc[i][0],
              residue - {i + 1},
          )
  
  
  d, g = map(int, input().split())
  
  pc = [list(map(int, input().split())) for _ in range(d)]
  
  ans = float("inf")
  
  dfs(0, 0, 0, set(range(1, d + 1)))
  print(ans)
  
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"}]