using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace laba_4
{
    class Program
    {
        static void Main(string[] args)
        {
            Task1 t1 = new Task1();
            Task2 t2 = new Task2();
            Console.WriteLine("Введите номер задания");
            int z = Convert.ToInt32(Console.ReadLine());
            switch (z)
            {
                case (1):t1.Calculate(Convert.ToInt32(Console.ReadLine()), Convert.ToDouble(Console.ReadLine()));
                    break;
                case (2): t2.IncSum(Convert.ToInt32(Console.ReadLine()), Convert.ToInt32(Console.ReadLine()));
                    break;
            }
            Console.ReadKey();
        }
    }
    class Task1
    {
        static int factorial(int i)
        {
            int result;
            if (i == 1)
                return 1;
            result = factorial(i - 1) * i;
            return result;
        }

        public double t1(int n)
        {
            double result = (Math.Pow((-1), n)) / factorial((n + 1));
            return result;
        }

        public double Calculate(int n, double m)
        {
            double sum = 0;
            for (int i = n; i <= m; i++)
            {
                sum += t1(i);
            }
            Console.WriteLine(sum);
            return sum;
        }
    }
    class Task2
    {
        public double IncSum(int a, int b)
        {
            int temp_a = a, temp_b = b;
            if (a == 0)
            {
                return b;
            }
            else if (b == 0)
            {
                return a;
            }
            if (a != temp_a + temp_b)
            {
                IncSum(a += 1, b -= 1);
            }
            if (a == temp_a + temp_b)
            {
                Console.WriteLine(a);
            }
            return a;
        }
    }
}