import strutils, sequtils


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 =
   let A, B = nextInt()
   [23, 24, 25].filterIt(it notin A..B).len.echo


when isMainModule:
   main()