Can't use Factorial method

New user here, i'll explain quickly the issue

When creating a console program, I tried to use this method inside the static void main

   int Factorial(int i)
            {if (i <= 1)
                    return 1;
                    return i * Factorial(i - 1);
            }

But as soon as I finished typing it, the compiler gives an error that occur in the void main's curly braces.

I already tried to set the method to public/static/public static

Please give detailed explanation, thanks in advance