internal class Program
{
static void Main(string[] args)
{
string firstName = "Сакутин";
string lastName = "Роман";
string temporary;

Console.WriteLine($"Фамилия - {lastName}, Имя - {firstName}.");

temporary = firstName;
firstName = lastName;
lastName = temporary;

Console.WriteLine($"Фамилия - {lastName}, Имя - {firstName}.");
}
}