I use Stata 14 on Windows.
I have a data set of 30,000 observations with multiple observations (different dates) on individuals identified with three string variables firstname middlename lastname of the following form

John Q Smith
John Q Smith
James Pearson Smith
James Pearson Smith
etc

Some individuals enter the data upwards of 200 times. I want to create a unique identifier for each individual, but the -encode command allows only a single variable. Any advice on how to create an identifier for each person?