05. Add and Subtract

using System;

namespace _05._Add_and_Subtract
{
    class Program
    {
        static void Main(string[] args)
        {
            double firstNumber = double.Parse(Console.ReadLine());
            double secondNumber = double.Parse(Console.ReadLine());
            double tirthNumber = double.Parse(Console.ReadLine());

            double sum = SumOfFirstSecond(firstNumber, secondNumber);

            Console.WriteLine(SubtractOfSumAndtirthNumber(sum, tirthNumber));
        }

        static double SumOfFirstSecond(double firstNumber,double secondNumber)
        {
            return firstNumber + secondNumber;
        }

        static double SubtractOfSumAndtirthNumber(double sum,double tirthNumber)
        {
            return sum - tirthNumber;
        }
    }
}