/**
* This is a function that calculates the length of a full name
* based on given first and last names. The method is
* not really implemented yet, but this is just a beta.
* @param {string} first_name First name
* @param {string} last_name Last name
* @return {int} The number of letters in a name
*/
function getFullNameLength(first_name, last_name) {
    //...
}