In dormitory of a hostel can accommodate six girls. Every dormitory has two bathrooms. The girls start using the bathrooms every morning from $7:00 \mathrm{am}$onwards. They use the bathroom one at a time, and sit down to eat breakfast together as soon as the last girl has finished. They spend $9, 11, 13, 18, 22$ and $23$ minutes in the bathroom respectively. Being well organized, what is the earliest they can have breakfast together?