You will initialize these sets by getting user input, one for each set. Each of the three inputs will contain the names of students that belong to that set, separated by whitespace. For instance, if your input is:

What is domain name system (dns)? allows dynamic ip address allocation so users do not have to have a preconfigured ip address to use the network converts ip addresses into domains, or identifying labels that use a variety of recognizable naming conventions the efficient coexistence of telephone, video, and data communication within a single network, offering convenience and flexibility not possible with separate infrastructures the integration of communication channels into a single service