Public bathing places in an area use a reservoir that has 4 (four) faucets for bathing showers. This container is filled with water from a well using 1 (one) pump which has 3 (three) speeds: low, medium and high. To avoid that the reservoir is not empty, the operation of the water pump is regulated as follows:
- if no shower is opened (all showers are closed), the water pump is off (off).
- if only 1 (one) shower is opened, the water pump is active (on) at low speed.
- if only 2 (two) showers are opened, the water pump is active (on) at medium speed.
- if 3 (three) or more showers are opened, the water pump is active (on) at high speed.

Design a digital circuit (draw a logic diagram) that will automatically activate the water pump according to the above conditions. (use as little IC as possible)