add and subtract

using System;
using System.Linq;
using System.Collections.Generic;
using System.Numerics;
using System.Text;

namespace exampreparation
{
    class exam
    {
        static void Main(string[] args)
        {
            int number1 = int.Parse(Console.ReadLine());
            int number2 = int.Parse(Console.ReadLine());
            int number3 = int.Parse(Console.ReadLine());

           int sum =  Sum(number1, number2);
           int substract = Substract(sum, number3);

            Console.WriteLine(substract);

        }

        static int Sum(int number1, int number2)
        {
            int sum = number1 + number2;
            return sum;
        }

        static int Substract(int sum, int number3)
        {
            int substract = sum - number3;
            return substract;
        }
    }
}