C#斐波那契数列递归算法

public static int Foo(int i)
        {
            if (i < 3)
            {
                return 1;
            }
            else
            {
                return Foo(i - 1) + Foo(i - 2);
            }
        }

static void Main(string[] args)
        {
            Console.WriteLine(Foo(8));
        }