Definition: In this task, you will use your knowledge about language (and common sense) to determine what element the marked number refers to. The numbers are marked with two underlines around them, like: _ number _. Your answer should be chosen from the given text, and should not contain other words.
Input: Fermín de Pablo:  Having received the message in words , I 'm preparing my report for the new contact , detailing my activities through today . I 've followed two lines of investigation . The first _ one _ , involving faculty members and service staff , has not brought about anything conclusive . The second one , involving the search for the items on the list , brought me to the location of piece number four in possession of Héctor de la Vega , the school 's ex - principal and , to this date , a possible suspect .

lines