import strutils


proc nextString: string =
   result = ""
   while not endOfFile stdin:
      let nextChar = readChar stdin
      case nextChar
      of '\r':
         discard
      of "\n"[0], ' ':
         break
      else:
         add result, nextChar


proc nextInt: int =
   return parseInt nextString()


proc main: void =
   var score = 0
   var bonus = 1

   var pf = nextInt()
   var gt = nextInt()
   let gd = nextInt()
   let ms = nextInt()

   if ms >= 10:
      echo("Impossible")
      return

   for i in 1..int.high:
      if gt == 0 and pf == 0:
         break
      elif gt != 0:
         score += 50 * bonus
         gt -= 1
      elif pf != 0:
         score += 100 * bonus
         pf -= 1

      if i mod 100 == 0:
         bonus *= 2

   echo score


when isMainModule:
   main()