递归算法计算斐波那契数列的第30个数

public class MainClass
{
    public static void Main() 
    {
        Console.WriteLine(Foo(30));
    }

    public static int Foo(int i)
    {
        if (i <= 0)
            return 0;
        else if(i > 0 && i <= 2)
            return 1;
        else return Foo(i -1) + Foo(i - 2);
    }
}