tt2q2_29m.cs

using System;
using System.Threading;

namespace Quiz29March
{
    public class Task2
    {

        public static void Main(string[] args)
        {

            int n = Int32.Parse(Console.ReadLine());
            
            new Thread(() =>
            {
                Factorial(n);
            }).Start();
            
            new Thread(() =>
            {
                Sum(n);
            }).Start();
        }
        
        public static void Factorial(long n)
        {
            long result = 1;
            for (long i = 2; i <= n; i++)
            {
                result *= i;
                Console.WriteLine("Считаю факториал");
                Thread.Sleep(500);
            }
            
            Console.WriteLine("Факториал: " + result);
        }

        public static void Sum(long n)
        {
            long result = 1;
            for (long i = 2; i <= n; i++)
            {
                result += i;
                Console.WriteLine("Считаю сумму");
                Thread.Sleep(500);
            }
            
            Console.WriteLine("Сумма: " + result);
        }        
        
    }
    
}