What is the output:

public class Countries
{
    public static void Display(string countryID)
    {
        Console.WriteLine("Country ID is " + countryID);
    }

    public void Display(int countryID)
    {
        Console.WriteLine("Country ID is " + countryID);
    }
}
class Africa
{
    static void Main()
    {
        Countries southafrica = new Countries();

        southafrica.Display("12");
    }
}