In the program you have to set day's limit of the time, which can be used for working on the computer. This limit can be different for every user of computer. The limit doesn't have to be used immediately. Each person who was limited by the program No mercy can use the computer every time and he doesn't have to use the whole time which is dedicated for this person - the person can use it "in parts". When limit is used up, the computer will switch off and after restart of the system user will have at the most one minute from logging on to another shutdown of the computer. This short period of the time is sufficient for the authorized user who can change settings in the progam No mercy if only it is needed (e.g to increase the user's time limit).