using System;

namespace ConsoleApp3
{
    internal class Program
    {
        static void Main(string[] args)
        {
            string name = "Иванов";
            string lastName = "Иван";
            string temporaryVariable;

            temporaryVariable = name;
            name = lastName;
            lastName = temporaryVariable;

            Console.WriteLine("Фамилия и Имя: " + lastName + " " + name);
        }