public static void Main()
Console.WriteLine("How many number do you want to add.");
x = int.Parse(Console.ReadLine());
for (int i = 1; i <= x; i++)
Console.WriteLine("Write the first number.");
sum += int.Parse(Console.ReadLine());
Console.WriteLine("Write the last number.");
sum += int.Parse(Console.ReadLine());
Console.WriteLine("Write a number.");
sum += int.Parse(Console.ReadLine());
Console.WriteLine("THE TOTAL ADDITION OF YOUR NUMBERS IS " + sum);