A free program for Android, by Сергей Попов.

This is a calendar app that allows you to easily manage your work schedule. It is suitable for people who work in shifts or have many responsibilities, such as teachers, doctors, or those who are the head of a household. 

It has a work mode that allows you to define the working hours for each day. This will help you remember what you have to do and when. It also has a calendar widget that allows you to quickly check the current date and time.

It is a free, easy-to-use calendar app that allows you to do the following: