message: Use floor division instead of regular division
  print Solution().sqrt(9) gave me 2.75, which should be 3.
diff: @@ -14,9 +14,9 @@ class Solution(object):
  if x < 2:
  return x
  - left, right = 1, x / 2
  + left, right = 1, x // 2
  while left <= right:
  - mid = left + (right - left) / 2
  + mid = left + (right - left) // 2
  if mid > x / mid:
  right = mid - 1
  else:
  