Vladimir Putin left the G20 summit in Australia yesterday, before the official end of discussions. The Russian president denied reports that tensions with western leaders were the cause of his early departure, and explained that he needed four hours of sleep before getting back to Moscow and resuming work. How much sleep do you need to function? Could you survive on four hours before a full day at work? Are you proud of not needing much sleep, and if so, do you wear it like a badge of honour, as Margaret Thatcher did? Or perhaps you like to be in bed before 9pm, in order to get a full 10 hours. Do you take your sleep routine seriously? Tell us what you need in order to be as tough as Putin the next day.