the hours of operation of two device

it monitors the operating hours of two pumps, we have one pump marked with HA1 and the second pump marked with HA2. On the column marked with "Pornit", write the time when the pump was started and on the column with "Oprit", write the time when it was stopped, they are recorded in the time interval 0 to 24 hours on a single day. there are several queues because in a day the pumps are turned on several times a day depending on the needs. then it is calculated independently for each cat that worked. Now I want to know how long the pumps stopped in the time interval from 0 am to 24 am, to see how much energy was not consumed from the system. the hours of energy consumption overlap, so it cannot be calculated twice, but must be calculated only as long as both have stopped