while f = gets
  a = f.to_f
  sum = a
  a *= 2.0
  sum += a
  a /= 3.0
  sum += a
  a *= 2.0
  sum += a
  a /= 3.0
  sum += a
  a *= 2.0
  sum += a
  a /= 3.0
  sum += a
  a *= 2.0
  sum += a
  a /= 3.0
  sum += a
  a *= 2.0
  sum += a
  puts sum
end