An apparatus comprises: selection circuitry to select the two most preferred items from a set of items having ranking information indicative of an order of preference for the set of items. The selection circuitry comprises at least one selection node circuit, each selection node circuit to receive as inputs an indication of a first pair of items and a second pair of items among the set of items, and comprises first selection circuitry and second selection circuitry. The first selection circuitry to first selection circuitry to select as a first selected item a most preferred one of: a most preferred ranked item of the first pair, and a least preferred item of the second pair. The second selection circuitry to select as a second selected item a most preferred one of: a least preferred item of the first pair, and a most preferred item of the second pair.