<image> A container with an inlet pipe and an outlet pipe starts filling with water only through the inlet pipe from a certain moment. After a period of time, the outlet pipe is opened to release water. At the 12th minute, the inlet pipe is shut off. During the time from the opening to the shutting off of the inlet pipe, the relationship between the amount of water y (in liters) in the container and the time x (in minutes) is shown in the figure. After shutting off the inlet pipe, the container will be completely emptied after ____ minutes.